Directional coupling communication apparatus

ABSTRACT

The invention relates to a directional coupling communication apparatus where the coupling impedance can be easily matched to reduce reflections, and thus, the speed of communication channels is increased as compared to that with inductive coupling, and at the same time, the reliability of communication is improved by increasing the signal intensity. Modules having a coupler where an input/output connection line is connected to a first end, and either a ground line or an input/output connection line to which an inverse signal of a signal to be inputted into the input/output connection line connected to the above-described first end is inputted is connected are layered on top of each other so that the couplers are couplers to each other using capacitive coupling and inductive coupling.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.14/408,797, filed on Dec. 17, 2014, which is a continuation ofInternational Application No. PCT/JP2013/067078 filed on Jun. 21, 2013,which is based upon and claims the benefit of priority from the priorJapanese Patent Application No. 2013-113066, filed on May 29, 2013 andJapanese Patent Application No. 2012-156874 filed on Jul. 12, 2012, theentire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a directional coupling communicationapparatus, and in particular, to a structure for non-contact datacommunication at high speed between modules or terminals usingcapacitive coupling and inductive coupling between a pair oftransmission lines in close proximity without using a contact typeconnector.

BACKGROUND ART

In the case where a system is constructed by combining modules accordingto the prior art, signal wires between modules are connected throughconnectors. In a mobile phone, for example, a display module or a cameramodule is connected to the main substrate in the main body through wiresand connectors on a flexible substrate.

When the characteristic impedance becomes discontinuous through aconnector, part of the signal is reflected, causing distortion in thesignal that has passed through. This causes inter-symbol interferenceand causes such a problem that an increase in the speed of communicationis hindered. In the case where the distance between the connectorterminals is reduced in order to increase the number of signals orminiaturize the connectors, crosstalk between signals increases, whichresults in an increase in the speed of communication and miniaturizationof the device being hindered.

In the case where the material for the connectors and the manufacturingprocess are more sophisticated in order to solve these problems, themanufacturing costs increase. In addition, it is difficult to automatethe work for connecting modules with connectors, and therefore, theassembly costs increase. These hinder the price of the device from beingreduced. Furthermore, there may be an incident such that a connectordisengages due to vibrations while the device is being used, whichlowers the reliability of the device.

The present inventor has proposed an electronic circuit for datacommunication between substrates or semiconductor integrated circuitchips using inductive coupling, that is to say, magnetic field coupling,through coils formed of wires on printed circuit boards (PCBs) andsemiconductor integrated circuit chips (see Non-Patent Documents 1 to3).

Meanwhile, it has also been proposed that microstrip lines or bus linesbe coupled in close proximity for wireless communication of data usingcapacitive coupling and inductive coupling (see Patent Documents 1 and2). Patent Document 1 discloses that differential transmission linesconsisting of two transmission lines placed parallel to each other andterminated for matching with a terminal resistor can be placed parallelto each other in the same direction for wireless communication betweentwo modules.

In addition, Patent Document 2 discloses that two microstrip lines thatare provided on a ground plane with a dielectric body film in betweenand are terminated for matching with a terminal resistor can be used asa directional coupler for wireless communication between two moduleswhen differential signals in a microwave band are inputted into the twomicrostrip lines.

PRIOR ART DOCUMENTS Patent Documents

-   Patent Document 1: Japanese Unexamined Patent Publication    2008-278290-   Patent Document 2: Japanese Unexamined Patent Publication    2007-049422

Non-Patent Documents

-   Non-Patent Document 1: H. Ishikuro, T. Sugahara, and T. Kuroda, “An    Attachable Wireless Chip Access Interface for Arbitrary Data Rate by    Using Pulse-Based Inductive-Coupling through LSI Package”, IEEE    International Solid-State Circuits Conference (ISSCC '07), Dig.    Tech. Papers, pp. 360-361, 608, February 2007-   Non-Patent Document 2: K. Niitsu, Y. Shimazaki, Y. Sugimori, Y.    Kohama, K. Kasuga, I. Nonomura, M. Saen, S. Komatsu, K. Osada, N.    Irie, T. Hattori, A. Hasegawa, and T. Kuroda, “An Inductive-Coupling    Link for 3D Integration of a 90 nm CMOS Processor and a 65 nm CMOS    SRAM”, IEEE International Solid-State Circuits Conference (ISSCC    '09), Dig. Tech. Papers, pp. 480-481, February 2009-   Non-Patent Document 3: S. Kawai, H. Ishikuro, and T. Kuroda, “A 2.5    Gb/s/ch Inductive-Coupling Transceiver for Non-contact Memory Card”,    IEEE International Solid-State Circuits Conference (ISSCC '10), Dig.    Tech. Papers, pp. 264-265, February 2010

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

In order to solve these problems relating to connectors, the presentinventor has proposed an apparatus for wireless data communication athigh speed between modules (or between devices) using capacitivecoupling and inductive coupling between transmission lines formed ofwires on electronic circuit substrates (see Patent Application2011-032886).

FIG. 52 is a schematic perspective diagram showing a communicationapparatus between modules proposed by the present inventor, wherecouplers have a differential structure with the resistance to same-phasenoise increased as compared to those with a single end. As shown in FIG.52, feedback lines 224 ₁ and 224 ₂ have the same structure as signallines 212 ₁ and 212 ₂ in order to provide differential couplers. In thiscase, the feedback lines 224 ₁, 224 ₂ and the signal lines 212 ₁, 212 ₂are terminated with resistors 214 ₁, 214 ₂ having a characteristicimpedance Z₀ that is equal to the coupling impedance Z_(0-coupled).

In the case of this proposal, the differential structure makes theresistance to same-phase noise high as compared to a structure with asingle end and makes it easy to control the coupling impedanceZ_(0-coupled) as compared to a structure with a single end.

FIG. 53 is a schematic perspective diagram showing another communicationapparatus between modules proposed by the present inventor, and in thisproposal, signal lines 212 ₁, 212 ₂ and feedback lines 224 ₁, 224 ₂ areall provided with lead transmission lines 225 ₁, 225 ₂, 226 ₁, and 226₂.

In this case as well, semiconductor integrated circuit apparatuses 215₁, 215 ₂, transmission lines 225 ₁, 225 ₂, 226 ₁, 226 ₂, signal lines212 ₁, 212 ₂, and feedback lines 224 ₁, 224 ₂ are respectively connectedfor impedance matching, and the terminals of the signal lines 212 ₁, 212₂ and the feedback lines 224 ₁, 224 ₂ are also impedance matched.

In the structures shown in FIGS. 52 and 53, however, four signal lines(212 ₁, 212 ₂, 224 ₁, 224 ₂) and two terminal resistors 214 ₁, 214 ₂ arerequired. In the case of FIG. 53, four lead transmission lines (225 ₁,225 ₂, 226 ₁, 226 ₂) are additionally required. Thus, such a problemremains that the number of parts is great and the volume of the terminalresistors is great, which makes the volume of mounted parts large withhigh costs.

In addition, four signal lines (212 ₁, 212 ₂, 224 ₁, 224 ₂) arecapacitively and inductively coupled to each other, which makes itrelatively difficult to match the coupling impedance, and thus, thereflection of signals easily occurs. Furthermore, such a problem remainsthat the value of the terminal resistors cannot be adjusted, and thus,the reflection of signals easily occurs.

Moreover, only near-end crosstalk that has been transmitted is used forsignal reception while far-end crosstalk is discarded as heat from theterminal resistors, and therefore, such a problem remains that theenergy of the signal that can be used for reception is small.

Accordingly, an object of the present invention is to reduce the numberof necessary parts in order to reduce the volume of mounted parts andthe costs so that matching can be made easier as a coupling impedance,and the value of the terminal resistors can be adjusted in order toreduce the reflection of signals, or the energy of the signals that canbe used for reception is increased so as to increase signal intensityand reliability for communication.

Means for Solving Problem

(1) In order to solve the above-described problems, a directionalcoupling communication apparatus is characterized by having: a firstmodule having a first coupler provided on a first insulating substrate,where an input/output connection line is connected to a first end, andeither a ground line or an input/output connection line to which aninverse signal of a signal to be inputted into the input/outputconnection line connected to the above-described first end is connectedto a second end; and a second module having a second coupler provided ona second insulating substrate, where an input/output connection line isconnected to a first end, and either a ground line or an input/outputconnection line to which an inverse signal of a signal to be inputtedinto the input/output connection line connected to the above-describedfirst end is connected to a second end, wherein the above-describedfirst module and the above-described second module are layered on top ofeach other so that the above-described first coupler and theabove-described second coupler overlap at least partially as viewed inthe direction in which the above-described first module and theabove-described second module are layered on top of each other, andsignal coupling occurs using capacitive coupling and inductive couplingbetween the above-described first coupler and the above-described secondcoupler.

Thus, electromagnetic field coupling is generated between the firstcoupler and the second coupler where an input/output connection line isconnected to one end and an input/output connection line or a groundline is connected to the other end so that only two signal lines form acoupler, and therefore, the number of necessary parts can be reduced ascompared to the prior art inventions in order to reduce the volume ofmounted parts, lower the cost, and make it relatively easy to match thecoupling impedance.

(2) In addition, the present invention provides the directional couplingcommunication apparatus according to the above (1), which ischaracterized in that the above-described first module and theabove-described second module are layered on top of each other in such astate that signal coupling between an input/output connection lineconnected to the above-described first coupler and an input/outputconnection line connected to the above-described second coupler isweaker than signal coupling between the above-described first couplerand the above-described second coupler.

Thus, it is desirable for the first coupler and the second coupler to belayered on top of each other in such a state that the signal couplingthat does not effectively contribute to communication between theinput/output connection line connected to the first coupler and theinput/output connection line connected to the second coupler is weakerthan the signal coupling that contributes to communication between thefirst coupler and the second coupler.

(3) Furthermore, the present invention provides the directional couplingcommunication apparatus according to the above (1) or (2), which ischaracterized in that at least one of the above-described first moduleand the above-described second module has a semiconductor integratedcircuit apparatus with a transmitter/receiver circuit connected to aninput/output connection line.

Thus, the semiconductor integrated circuit apparatus with atransmitter/receiver circuit may be provided to at least one of thefirst module and the second module. In the case where the semiconductorintegrated circuit apparatus is provided to both, direct communicationis created between the two. In the case where the semiconductorintegrated circuit apparatus is provided to only one module, the othermodule handles the mediation for communication.

(4) Furthermore, the present invention provides the above (3), which ischaracterized in that an impedance matching circuit is connected to aninput/output terminal of the above-described transmitter/receivercircuit provided in the above-described semiconductor integrated circuitapparatus.

When an impedance matching circuit is connected to an input/outputterminal of the transmitter/receiver circuit, matching termination canbe achieved on the semiconductor integrated circuit apparatus sidewithout using a terminal resistor, and as a result, signal reflectioncan be suppressed.

(5) In addition, the present invention provides any of the above (1) to(4), which is characterized in that the input/output connection line isconnected to the second end of the above-described first coupler, andthe input/output connection line is connected to the second end of theabove-described second coupler.

By providing such a structure where a differential signal is inputtedthrough the two ends of a coupler, the far end crosstalk, which wasdiscarded as heat according to the prior art, strengthens the signal,and therefore, the reliability in communication increases. That is tosay, the far end crosstalk for the (+) signal strengthens the near endcrosstalk for the (−) signal while the far end crosstalk for the (−)signal strengthens the near end crosstalk for the (+) signal, and thus,the received signal is strengthened. In addition, (+) and (−) signalsare always applied to the two ends of a coupler, and therefore, thecommon signal does not change, which makes unnecessary radiation (noise)lower.

(6) Furthermore, the present invention provides the above (5), which ischaracterized in that a connection portion of the input/outputconnection lines connected to the two ends of the above-described firstcoupler runs in the direction of a long axis of the above-describedfirst coupler, and a connection portion of the input/output connectionlines connected to the two ends of the above-described second couplerruns in the direction of a long axis of the above-described secondcoupler.

By adopting such a connection structure, signals that transmit throughcouplers do not have a different current intensity in the direction ofthe width of the first coupler and the second coupler, and therefore,communication with high precision becomes possible.

(7) Moreover, the present invention provides the above (5), which ischaracterized in that a connection portion of the input/outputconnection lines connected to the two ends of the above-described firstcoupler is connected to an end on a side along the direction of a longaxis of the above-described first coupler, and a connection portion ofthe input/output connection lines connected to the two ends of theabove-described second coupler is connected to an end on a side alongthe direction of a long axis of the above-described second coupler.

By adopting such a connection structure, it is possible to miniaturizethe input/output connection lines, including couplers.

(8) In addition, the present invention provides any of the above (5) to(7), which are characterized in that at least one of the above-describedfirst coupler and the above-described second coupler is mounted on aprotrusion, and a neighborhood of a connection portion of theabove-described input/output connection lines of the coupler mounted onthe above-described protrusion is provided along a side of theabove-described protrusion.

Thus, by mounting at least one coupler on top of a protrusion, the firstcoupler and the second coupler can be made to face each other at anarbitrary distance without taking the thickness of the semiconductorintegrated circuit apparatus into consideration.

(9) Furthermore, the present invention provides the above (5), which ischaracterized in that an input/output connection line connected to theabove-described first coupler and an input/output connection lineconnected to the above-described second coupler are bonding wires. Thus,bonding wires may be used as the input/output connection lines thatconnect the couplers to the transmitter/receiver circuit.

(10) Moreover, the present invention provides any of the above (5) to(8), which are characterized in that an input/output connection lineconnected to the above-described first coupler and an input/outputconnection line connected to the above-described second coupler aresignal lines. Thus, signal lines may be used as the input/outputconnection lines for connecting the couplers to the transmitter/receivercircuit, which makes it possible to install the transmitter/receivercircuit in a place away from the couplers, and furthermore makes theinput/output connection line through which a (+) signal is applied andthe input/output connection line through which a (−) signal is appliedhave the same length with high precision.

(11) In addition, the present invention provides any of the above (1) to(4), which are characterized in that the ground line is connected to thesecond end of the above-described first coupler, and the ground line isconnected to the second end of the above-described second coupler.

Thus, the second end of a coupler may be connected to the ground line sothat an input signal is reflected from the second end that is connectedto the ground line, and a reflected signal with reverse polarityprogresses from the second end to the first end, and therefore, the farend crosstalk strengthens the signal in the same manner as when adifferential signal is inputted through the two ends of the coupler,which increases the reliability in communication.

(12) Furthermore, the present invention provides any of the above (1) to(11), which are characterized in that the length of the above-describedfirst coupler is greater than the length of the above-described secondcoupler. Thus, the couplers can have different lengths so as to have agreat positioning margin when modules are layered on top of each other.

(13) Moreover, the present invention provides any of the above (1) to(12), which are characterized in that a long axis of the above-describedfirst coupler and a long axis of the above-described second coupler arenot parallel to each other. Thus, the long axes of the couplers can bemade unparallel to each other so as to have a great positioning marginas well when modules are layered on top of each other.

(14) In addition, the present invention provides the above (5), which ischaracterized in that the above-described first coupler and theabove-described second coupler have a shape that has been bent a numberof times so that the two ends of the coupler approach each other. Thus,it is not necessary for the couplers to be rectangular, and they mayhave such a shape as to be bent a number of times so that the two endsof the coupler approach each other, for example, in a C shape, whichmakes it easy for the entire structure to be compact, where theinput/output signal lines can have the same length or be shortened.

(15) Furthermore, the present invention provides any of the above (1) to(14), which are characterized in that at least either an area on theside opposite to a surface of the above-described first insulatingsubstrate on which the above-described first coupler is provided or anarea on the side opposite to a surface of the above-described secondinsulating substrate on which the above-described second coupler isprovided has an electromagnetic shield layer. Thus, the electromagneticshield layer can be provided so as to reduce the electromagnetic fieldnoise that enters from the outside, and as a result, noise resistancecan be further increased.

(16) Moreover, the present invention provides the above (15), which ischaracterized in that the above-described electromagnetic shield layerhas a missing portion in a location facing the above-described firstcoupler or the above-described second coupler. Thus, a missing portionis provided to the electromagnetic shield layer so that electric linesof force can be concentrated between the couplers in order to increasethe degree of coupling between the couplers. Furthermore, this structureis indispensible in the case where the two modules are layered on top ofeach other in the same direction instead of being layered on top of eachother so as to face each other.

(17) In addition, the present invention provides any of the above (1) to(4), which are characterized in that a third coupler, where aninput/output connection line is connected to a first end, and either aground line or an input/output connection line to which an inversesignal of a signal to be inputted into the input/output connection lineconnected to the above-described first end is connected to a second end,is provided on the above-described first insulating substrate in theabove-described first module, and a third module provided with a fourthcoupler, where an input/output connection line is connected to a firstend, and either a ground line or an input/output connection line towhich an inverse signal of a signal to be inputted into the input/outputconnection line connected to the above-described first end is connectedto a second end, on an insulating substrate is layered so that theabove-described third coupler and the above-described fourth coupleroverlap at least partially as viewed in the direction in which theabove-described third module is layered, and signal coupling occursusing capacitive coupling and inductive coupling between theabove-described third coupler and the above-described fourth coupler.

Thus, the number of modules is not limited to two, but rather three ormore modules may be provided.

(18) Furthermore, the present invention provides the above (17), whichis characterized in that the two ends of the above-described thirdcoupler and the two ends of the above-described first coupler areconnected with wires having the same length, and the above-describedfirst module mediates communication between the above-described secondmodule and the above-described third module.

In this case, it is possible to use the first module as an interposer orin the same manner as for a motherboard so as to mediate communicationbetween the second module and the third module.

(19) Moreover, the present invention provides any of the above (1) to(4), which are characterized in that the first coupler provided on theabove-described first insulating substrate in the above-described firstmodule has a length that corresponds to at least two couplers, and athird module provided with a fourth coupler, where an input/outputconnection line is connected to a first end, and either a ground line oran input/output connection line to which an inverse signal of a signalto be inputted into the input/output connection line connected to theabove-described first end is connected to a second end, on an insulatingsubstrate is layered so that the above-described first coupler and theabove-described fourth coupler overlap at least partially as viewed inthe direction in which the above-described third module is layered, andsignal coupling occurs using capacitive coupling and inductive couplingbetween the above-described first coupler and the above-described fourthcoupler.

Thus, the first coupler may be formed so as to have such a length thatcan correspond to at least two couplers instead of the provision of athird coupler, and as a result, a multi-drop bus for communication witha number of modules can be formed.

(20) In addition, the present invention provides any of the above (1) to(4), which are characterized in that a third module provided with athird coupler, where an input/output connection line is connected to afirst end, and either a ground line or an input/output connection lineto which an inverse signal of a signal to be inputted into theinput/output connection line connected to the above-described first endis connected to a second end, is layered on a surface of theabove-described first insulating substrate on the side opposite to asurface on which the above-described second module is layered so thatsignal coupling occurs using capacitive coupling and inductive couplingbetween the above-described first coupler and the above-described thirdcoupler.

Such a structure can also make communication between a number of modulespossible. In this case, direct communication between the second couplerand the third coupler is blocked because the first coupler works as ashield.

(21) Furthermore, the present invention provides any of the above (17),(19), or (20), which are characterized in that the above-described firstmodule is equipped with a semiconductor integrated circuit apparatusthat works as a microprocessor, and the above-described second moduleand the above-described third module are equipped with a semiconductorintegrated circuit apparatus that works as a semiconductor memoryapparatus for communicating with the above-described microprocessor.

Thus, as a typical example of communication using three or more modules,communication between one microprocessor and a number of semiconductorintegrated circuit apparatuses controlled by the microprocessor can becited.

(22) Moreover, the present invention provides any of the above (1) to(4), which are characterized in that a dielectric body in plate form forintensifying the electromagnetic field coupling is inserted between theabove-described first coupler and the above-described second coupler.Thus, the dielectric body in plate form is inserted between the firstcoupler and the second coupler so that electromagnetic field coupling ispossible between the first coupler and the second coupler even when thedistance between the two is great.

(23) In addition, the present invention provides the above (17) or (18),which are characterized in that the above-described first coupler andthe above-described third coupler are formed of two couplers and areterminal resistors for linking the two couplers respectively. Thus, thefirst coupler and the third coupler that form a closed circuit arerespectively formed of two couplers and a terminal resistor for linkingthe two couplers so that the evenness of the degree of coupling can bemaintained for a broadband and signal distortion can be reduced.

(24) Furthermore, the present invention provides either the above (1) or(4), which are characterized in that the above-described first couplerand the above-described second coupler are couplers in arc form havingthe same curvature radius. Thus, the first coupler and the secondcoupler are couplers in arc form so that lead transmission lines fromthe first module and the second module can be led out at an arbitraryangle.

(25) Moreover, the present invention provides the above (24), which ischaracterized in that the center of the above-described second couplerin the above-described second module matches with the center of theabove-described first coupler in the above-described first module, andthe above-described second module is freely rotatable around theabove-described first module. Thus, the second module is provided so asto be freely rotatable around the first module, which makescommunication between the operating members through electromagneticfield coupling possible.

(26) In addition, the present invention provides the above (24) or (25),which are characterized in that the length of an arc of theabove-described second coupler is shorter than the length of an arc ofthe above-described first coupler. Thus, in the case of couplers in arcform, a good degree of coupling can be maintained even when the lengthof the arc in each coupler is not the same.

(27) Furthermore, the present invention provides any of the above (1) to(4), which are characterized by further having: a third module having athird coupler provided on a third insulating substrate, where aninput/output connection line is connected to a first end, and either aground line or an input/output connection line to which an inversesignal of a signal to be inputted into the input/output connection lineconnected to the above-described first end is connected to a second end,wherein the above-described first to third modules are layered on top ofeach other so that the above-described first coupler, theabove-described second coupler, and the above-described third coupleroverlap at least partially as viewed in the direction in which theabove-described first to third modules are layered on top of each other,and signal coupling occurs using capacitive coupling and inductivecoupling between the above-described first coupler, the above-describedsecond coupler, and the above-described third coupler.

In this manner, the three modules can be layered on top of each other sothat the couplers overlap in the direction in which the modules arelayered, and thus, a multi-drop bus can be formed with any one moduleacting as a bus. As a result, it is possible for the module acting as abus to simultaneously communicate with the other two modules.

(28) Moreover, the present invention provides any of the above (1) to(4), which are characterized in that a third module having a thirdcoupler is layered on a surface of the above-described first insulatingsubstrate on the side opposite to a surface on which the above-describedfirst module is layered so that a longitudinal direction of theabove-described first coupler and a longitudinal direction of the thirdcoupler cross at right angles. Thus, the third coupler can be providedon the rear surface of the same substrate so as to preventelectromagnetic interference between the first coupler and the thirdcoupler.

(29) In addition, the present invention provides a directional couplingcommunication apparatus, which is characterized by having: a firstcoupler in arc form provided on a first insulating substrate, where aninput/output connection line is connected to a first end, and either aground line or an input/output connection line to which an inversesignal of a signal to be inputted to the input/output connection lineconnected to the above-described first end is inputted is connected; anda second coupler in arc form, where an input/output connection line isconnected to a first end, and either a ground line or an input/outputconnection line to which an inverse signal of a signal to be inputted tothe input/output connection line connected to the above-described firstend is inputted is connected, wherein the diameter of a coupler in theabove-described second coupler in smaller than the diameter of a couplerin the above-described first coupler, and the above-described secondcoupler is incorporated inside the above-described first coupler so asto be freely rotatable around the above-described first coupler in aconcentric manner. Thus, the second coupler can be incorporated insidethe first coupler so as to be freely rotatable around the first couplerin a concentric manner and work as an electromagnetic field connector inthe rotatable portion.

(30) Furthermore, the present invention provides the above (26) or (29),which are characterized in that the above-described first coupler andthe above-described second coupler are provided to a hinge portion of ahousing that can be freely opened and closed. Thus, as anelectromagnetic field connector in the rotatable portion, a connector istypically provided in a hinge portion of a housing that can be freelyopened and closed.

Effects of the Invention

The disclosed directional coupling communication apparatus makesmatching easier as a coupling impedance so as to reduce reflection, andmakes it possible for the communication channel to be faster (broadband)than inductive coupling and for the signal intensity to be increased soas to improve the reliability of communication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram showing the structure of the directionalcoupling communication apparatus according to an embodiment of thepresent invention;

FIGS. 2A to 2C are schematic diagrams showing portions of the structureof the directional coupling communication apparatus according to theembodiment of the present invention;

FIG. 3 is a schematic cross-sectional diagram showing the directionalcoupling communication apparatus according to the embodiment of thepresent invention;

FIGS. 4A to 4C are a diagram and graphs for showing the operationalprinciple (1) of the directional coupling communication apparatusaccording to the embodiment of the present invention;

FIGS. 5A to 5F are graphs for showing the operational principle (2) ofthe directional coupling communication apparatus according to theembodiment of the present invention;

FIGS. 6A to 6D are graphs for showing the operational principle (3) ofthe directional coupling communication apparatus according to theembodiment of the present invention;

FIGS. 7A and 7B are diagrams showing the structure of the directionalcoupling differential communication apparatus according to Example 1 ofthe present invention;

FIGS. 8A to 8C are diagrams showing the structure of coupler elementsused in Example 1 of the present invention;

FIG. 9 is a cross-sectional diagram showing the state of the layers ofthe coupler elements used in Example 1 of the present invention;

FIG. 10 is a circuit diagram showing the transmitter/receiver circuitused in Example 1 of the present invention;

FIGS. 11A and 11B are diagrams showing the directional couplingdifferential communication apparatus according to Example 2 of thepresent invention;

FIGS. 12A to 12C are diagrams showing the coupler elements for formingthe directional coupling differential communication apparatus accordingto Example 3 of the present invention;

FIG. 13 is a plan diagram showing the coupler elements for forming thedirectional coupling differential communication apparatus according toExample 4 of the present invention;

FIGS. 14A to 14C are diagrams showing the coupler elements for formingthe directional coupling differential communication apparatus accordingto Example 5 of the present invention;

FIGS. 15A to 15C are diagrams showing the coupler elements for formingthe directional coupling differential communication apparatus accordingto Example 6 of the present invention;

FIG. 16 is a plan diagram showing the coupling state of the couplerelements for forming the directional coupling differential communicationapparatus according to Example 7 of the present invention;

FIGS. 17A to 17C are diagrams showing the coupler elements for formingthe directional coupling differential communication apparatus accordingto Example 8 of the present invention;

FIG. 18 is a cross-sectional diagram showing the vicinity of the couplerelements for forming the directional coupling differential communicationapparatus according to Example 9 of the present invention;

FIG. 19 is a circuit diagram the transmitter/receiver circuit used inthe directional coupling differential communication apparatus accordingto Example 10 of the present invention;

FIG. 20 is a schematic diagram showing the structure of the directionalcoupling differential communication apparatus according to Example 11 ofthe present invention;

FIGS. 21A to 21C are schematic diagrams showing the structure of thedirectional coupling differential communication apparatus according toExample 11 of the present invention;

FIG. 22 is a cross-sectional diagram concretely showing the structure ofthe directional coupling differential communication apparatus accordingto Example 11 of the present invention;

FIGS. 23A and 23B are diagrams showing a case where the first module andthe second module are formed of a semiconductor chip;

FIG. 24 is a cross-sectional diagram showing the directional couplingdifferential communication apparatus according to Example 12 of thepresent invention;

FIGS. 25A to 25C are schematic diagrams showing the structure of thedirectional coupling differential communication apparatus according toExample 13 of the present invention;

FIGS. 26A and 26B are diagrams showing the structure of the directionalcoupling differential communication apparatus according to Example 14 ofthe present invention;

FIG. 27 is a schematic diagram showing the structure of the directionalcoupling differential communication apparatus according to Example 15 ofthe present invention;

FIG. 28 is a cross-sectional diagram showing the concrete structure ofthe directional coupling differential communication apparatus accordingto Example 15 of the present invention;

FIG. 29 is a schematic diagram showing the structure of the directionalcoupling differential communication apparatus according to Example 16 ofthe present invention;

FIG. 30 is a cross-sectional diagram showing the concrete structure ofthe directional coupling differential communication apparatus accordingto Example 16 of the present invention;

FIG. 31 is a schematic diagram showing the structure of the directionalcoupling differential communication apparatus according to Example 17 ofthe present invention;

FIG. 32 is a cross-sectional diagram showing the concrete structure ofthe directional coupling differential communication apparatus accordingto Example 11 of the present invention;

FIGS. 33A to 33C are diagrams showing the structure of a module forforming the directional coupling communication apparatus according toExample 18 of the present invention;

FIGS. 34A to 34C are a diagram and graphs for showing the operationalprinciple (1) of the directional coupling communication apparatusaccording to Example 18 of the present invention;

FIGS. 35A to 35F are graphs for showing the operational principle (2) ofthe directional coupling communication apparatus according to Example 18of the present invention;

FIGS. 36A to 36D are graphs for showing the operational principle (3) ofthe directional coupling communication apparatus according to Example 18of the present invention;

FIGS. 37A to 37C are graphs for showing the operational principle (4) ofthe directional coupling communication apparatus according to Example 18of the present invention;

FIGS. 38A and 38B are diagrams showing the structure of the directionalcoupling differential communication apparatus according to Example 19 ofthe present invention;

FIGS. 39A and 39B are diagrams showing the structure of the directionalcoupling differential communication apparatus according to Example 20 ofthe present invention;

FIG. 40 is a graph showing the results of electromagnetic fieldsimulation;

FIGS. 41A to 41C are schematic diagrams showing the structure of thedirectional coupling differential communication apparatus according toExample 21 of the present invention;

FIGS. 42A to 42C are schematic diagrams showing the structure of thedirectional coupling differential communication apparatus according toExample 22 of the present invention;

FIGS. 43A and 43B are schematic diagrams showing the structure of thedirectional coupling differential communication apparatus according toExample 23 of the present invention;

FIG. 44 is a schematic diagram showing the structure of the directionalcoupling differential communication apparatus according to Example 24 ofthe present invention;

FIG. 45 is a diagram showing the directional coupling differentialcommunication apparatus according to Example 25 of the presentinvention;

FIGS. 46A to 46C are diagrams showing the direction in which lead outtransmission lines are led out;

FIGS. 47A to 47C are schematic diagrams showing the structure of thedirectional coupling differential communication apparatus according toExample 26 of the present invention;

FIGS. 48A to 48C are schematic diagrams showing the structure of thedirectional coupling differential communication apparatus according toExample 27 of the present invention;

FIGS. 49A to 49C are graphs showing the dependency of the degree ofcoupling on the angle θ;

FIGS. 50A to 50C are schematic diagrams showing the structure of thedirectional coupling differential communication apparatus according toExample 28 of the present invention;

FIGS. 51A to 51C are schematic diagrams showing the structure of thedirectional coupling differential communication apparatus according toExample 29 of the present invention;

FIG. 52 is a schematic perspective diagram showing an inter-modulecommunication apparatus that had been proposed by the present inventor;and

FIG. 53 is a schematic perspective diagram showing another inter-modulecommunication apparatus that had been proposed by the present inventor.

PREFERRED EMBODIMENTS OF THE INVENTION

The directional coupling communication apparatus according to anembodiment of the present invention is described below in reference toFIGS. 1 to 6D. FIG. 1 is a schematic diagram showing the structure ofthe directional coupling communication apparatus according to anembodiment of the present invention, where a first module 10 ₁ having afirst coupler 12 ₁ and a transmitter/receiver circuit 15 ₁ and a secondmodule 10 ₂ having a second coupler 12 ₂ and a transmitter/receivercircuit 15 ₂ are layered on top of each other in such a manner that thefirst coupler 12 ₁ and the second coupler 12 ₂ at least partiallyoverlap in the direction in which the first module 10 ₁ and the secondmodule 10 ₂ are layered on top of each other, and thus, signal couplingis generated between the first coupler 12 ₁ and the second coupler 12 ₂through electromagnetic field coupling, that is to say, capacitivecoupling and inductive coupling. Though not necessary, it is desirableto achieve impedance matching by adjusting the input/output impedance ofthe transmitter/receiver circuit 15 ₁ and the transmitter/receivercircuit 15 ₂ so that it is equal to the coupling impedance Z_(0-coupled)during the time when the first coupler 12 ₁ and the second coupler 12 ₂are in a coupled state.

The objects to which the present invention is applied is a field wherethe system is treated as a distributed constant circuit of which theassumption is that each coupler has a length longer than the signalwavelength, typically 1/10 of the signal wavelength or longer, and thus,the objects are totally different than coils that can be handled as alumped constant circuit.

FIGS. 2A to 2C are schematic diagrams showing the structure of parts ofthe directional coupling communication apparatus according to theembodiment of the present invention, where FIG. 2A is a plan diagramshowing the first module, FIG. 2B is a plan diagram showing the secondmodule, and FIG. 2C is a perspective plan diagram showing the secondmodule in the case where it is layered inversely from front to rear. Asshown in FIG. 2A, the first coupler 12 ₁ is formed on a first insulatingsubstrate 11 ₁, and input/output connection lines 13 ₁ and 14 ₁ areconnected to the two ends of the first coupler 12 ₁. In addition, asshown in FIG. 2B, the second coupler 12 ₂ is formed on a secondinsulating substrate 11 ₁ in the same manner as in the first module 10₁, where input/output connection lines 13 ₂ and 14 ₂ are connected tothe two ends of the second coupler 12 ₂. In this case, the input/outputconnection lines 13 ₂ and 14 ₂ are parts that do not effectivelycontribute to communication, and therefore are provided in such a mannerthat the coupled state is weaker than the electromagnetic field couplingbetween the first coupler 12 ₁ and the second coupler 12 ₂ thatcontribute to communication.

FIG. 2C is a perspective plan diagram showing the second module in thecase where it is layered inversely from front to rear, where thedirection in which the input/output connection lines 13 ₁ and 14 ₁ areled out from the first module 10 ₁ and the direction in which theinput/output connection lines 13 ₂ and 14 ₂ are led out from the secondmodule 10 ₂ are opposite to each other, and therefore, theelectromagnetic field coupling between the input/output connection lines13 ₁, 14 ₁, and the input/output connection lines 13 ₂, 14 ₂ can begreatly reduced.

Though the input/output connection lines 13 ₁, 14 ₁ and the input/outputconnection lines 13 ₂, 14 ₂ are formed as signal lines to which adistributed constant circuit is applied, bonding wires may be used. Inaddition, though the connection portions between the input/outputconnection lines 13 ₁, 14 ₁ and the input/output connection lines 13 ₂,14 ₂ run in the direction of the long axes of the first coupler 12 ₁ andthe second coupler 12 ₂, the input/output connection lines 13 ₁, 14 ₁and the input/output connection lines 13 ₂, 14 ₂ may respectively beconnected to the ends of sides of the first coupler 12 ₁ and the secondcoupler 12 ₂ along the long axis.

Furthermore, it is not necessary for the first coupler 12 ₁ and thesecond coupler 12 ₂ to have the same length, and they may have a lengthdifferent from each other. Alternatively, the long axes of the firstcoupler 12 ₁ and the second coupler 12 ₂ may not be parallel to eachother so that the margin for positioning at the time of layering can beincreased. Moreover, it is not necessary for the first coupler 12 ₁ andthe second coupler 12 ₂ to be rectangular, and for example, they may bein C shape where there are two bends. As another alternative, they maybe in such a shape that the two ends of the C shape are bent so that theshape has four bends in total. Thus, the couplers have such a shape thatthe two ends are close to each other in such a manner that theconnection portions between the coupler and the input/output connectionlines are in close proximity, and therefore, the couplers having thesame coupling length can be made compact.

FIG. 3 is a schematic cross-sectional diagram showing the directionalcoupling communication apparatus according to the embodiment of thepresent invention, where electromagnetic shield layers 16 ₁ and 16 ₂ arerespectively formed on the rear surface of the first insulatingsubstrate 11 ₁ and the second insulating substrate 11 ₂ having arelative dielectric constant ε₂, and missing portions 17 ₁ and 17 ₂ areprovided in the portions of the electromagnetic shield layers 16 ₁ and16 ₂ that face the first coupler 12 ₁ and the second coupler 12 ₂ inorder to increase the degree of coupling.

In addition, surface layers 18 ₁, 18 ₂, 19 ₁, and 19 ₂ having a relativedielectric constant ε₃ are formed on the front and rear of the firstinsulating substrate 11 ₁ and the second insulating substrate 11 ₂ forprotection. The first module 10 ₁ and the second module 10 ₂ are layeredon top of each other so as to face each other with a space or aninsulating film of which the relative dielectric constant is ε₁.

Resins such as a polyimide resin, an epoxy resin, a phenol resin, and anacryl resin may be used as the material for the first insulatingsubstrate 11 ₁, the second insulating substrate 11 ₂, the surface layers18 ₁, 18 ₂, 19 ₁, 19 ₂, and the insulating film, where it is desirablefor the setting to be ε₁<ε₂<ε₃. In order to set the relative dielectricconstant at any value, it may be adjusted by the selection of the typeof base resin and additives. As for the substrates, flexible printedcircuits (FPCs) having any of the above-described resins as a base areflexible and have a thickness as thin as approximately 75 μm, and thusare easily mounted in a small apparatus such as a mobile phone. However,the substrates are not limited to FPCs, and printed circuit boards(PCBs), semiconductor substrates, and substrates within a package may beused.

In the case where the dielectric constant between the coupler lines islower than the dielectric constant of the material around the couplerlines, the crosstalk in the near ends becomes smaller and the crosstalkin the far ends becomes greater, and therefore, the reliability ofcommunication can be secured by using the crosstalk between the farends. As a result, a gap may be left between the two modules when theyare provided in close proximity, for example, which has such anadvantage that the connection of modules is easy and at a low cost.Alternatively, the selection of an insulating film at the time of closeconnection with an insulating film in between can be more varied.

Next, the operational principle of the directional couplingcommunication apparatus according to the embodiment of the presentinvention is described in reference to FIGS. 4A to 6D. First, as shownin FIG. 4A, the input end for a (+)₁ signal of the first coupler 12 ₁ isterminal A₁, and the input end for a (−)₁ signal of the first coupler 12₁ is terminal B₁. Likewise, the output end for a (+)₂ signal of thesecond coupler 12 ₂ is terminal A₂, and the output end for a (−)₂ signalof the second coupler 12 ₂ is terminal B₂.

FIG. 4B is a waveform diagram showing an example of the (+)₁ signal, andFIG. 4C is a waveform diagram showing the (−)₁ signal having an oppositepolarity and corresponding to the (+)₁ signal, where the (+)₁ signal andthe (−)₁ signal form a differential signal. Here, the signal waveformhas an amount of time RT respectively for rising and falling.

When the signal (+)₁ propagates from the terminal A₁ of the firstcoupler 12 ₁ towards the terminal B₁, the current and the voltage changeat the crest of a wave of the signal that propagates. Mutual capacitanceC and mutual inductance M exist continuously between the first coupler12 ₁ and the second coupler 12 ₂, and therefore, a capacitive couplingcurrent and an inductive coupling current are induced in the secondcoupler 12 ₂ so as to flow due to the coupling effects of i=C (dv/dt)and v=L (di/dt).

After a displacement current flows from the first coupler 12 ₁ to thesecond coupler 12 ₂, the impedance of the second coupler 12 ₂ is equalas viewed in the left and right directions from that point, andtherefore, the capacitive coupling current branches equally to the leftand right and flows to the two ends. That is to say, half of thecapacitive coupling current returns back to the near end (terminal A₂)and the other half proceeds to the far end (terminal B₂). Either currentgenerates a positive voltage signal in the terminal resistor located inthe point to which the current flows. Here, there are terminal resistorsfor matching termination in the transmitter/receiver circuit 15 ₁ and 15₂ shown in FIG. 1.

The signal that returns back to the near end (terminal A₂) has awaveform shown in FIG. 5A since the crest of the wave that is itscurrent signal source proceeds from the terminal A₁ towards the terminalB₁ through the first coupler 12 ₁ while returning back towards theterminal A₂ through the second coupler 12 ₂ at the same speed.

That is to say, a signal that propagates through the first coupler 12 ₁completely enters into the first coupler 12 ₁ after the amount of timeRT for the wave to rise since the crest of the wave of the signal hasentered into the terminal A₁, and while the signal propagates towardsthe terminal B₁, half of the displacement current that has emitted fromthe current signal source that progresses towards the terminal B₁returns back towards the terminal A₂ at the same speed, and therefore,the terminal A_(z) has a constant current value. When the time it takesfor the signal (+)₁ to propagate from the terminal A₁ to the terminal B₂is TD, at the point in time when the signal has reached the terminal B₁,half of the displacement current that has moved to the second coupler 12₂ returns to the terminal A₂ of the second coupler 12 ₂, takingadditional time TD, and therefore, the coupling signal (+)₂ that appearsat the terminal A₂ becomes a pulse signal with a time width of 2TD asshown in FIG. 5A.

In addition, the remaining half of the current that progresses towardsthe terminal B₂ reaches the terminal B₂ after TD while accumulating theamount of current together with the current signal source since itprogresses towards the terminal B₁, and thus, a waveform as shown inFIG. 5B is provided.

Meanwhile, the inductive coupling current is a current that flows due tothe voltage supply that is induced in the second coupler 12 ₂ throughinductive coupling, and the direction thereof is opposite to thedirection of the current loop in the first coupler 12 ₁ and is directedfrom the terminal B₂ to the terminal A₂ macroscopically, and thus, awaveform as shown in FIG. 5C is provided. Accordingly, the signalgenerated at the terminal A₂ through inductive coupling has the samesymbol as the signal generated at the terminal A₂ through capacitivecoupling so that the signals strengthen each other and a waveform asshown in FIG. 5E is provided.

Furthermore, the signal generated at the terminal B₂ has the symbolopposite to that of the signal generated at the terminal B₂ throughcapacitive coupling as shown in FIG. 5D so that the signals weaken eachother, and as a result, as shown in FIG. 5F, a negative signalpropagates through the terminal B₂ in many cases.

That is to say, the signal (+)₁ that has been inputted from the terminalA₁ generates a coupling signal (+)₂ having the same polarity applied tothe terminal A₂ by means of the coupler, and at the same time generatesthe coupling signal (+)₂ having the opposite polarity at the terminalB₂. Meanwhile, the signal (−)₁ that has been inputted from the terminalB₁ generates a coupling signal (−)₂ having the opposite polarity at theterminal A₂ by means of the coupler as shown in FIG. 6A and generates acoupling signal (−)₂ having the same polarity at the terminal B₂ asshown in FIG. 6B.

Accordingly, at the terminal A₂, the coupling signal (+)₂ and thecoupling signal (−)₂ both have the same polarity as the signal (+)₁ soas to strengthen each other and generate the signal in FIG. 6C throughoverlapping. Likewise, at the terminal B₂, the coupling signal (+)₂ andthe coupling signal (−)₂ both have a polarity opposite to the signal(+)₁ so as to strengthen each other and generate the signal in FIG. 6Dthrough overlapping. As a result, the digital signal that has beeninputted into the first module 10 ₁ can be received by the second module10 ₂ in the case where the polarity is determined near the center of thedifferential signal (+)₂−(−)₂.

Here, when the signal (+)₁ that has been inputted from the terminal A₁generates a coupling signal (+)₂ having the same polarity at theterminal A₂ by means of a coupler, this is referred to as crosstalk inthe near ends, and when it generates a coupling signal (+)₂ having theopposite polarity at the terminal B₂, this is referred to as crosstalkin the far ends. That is to say, when the signal (−)₁ that has beeninputted from the terminal B₁ generates a coupling signal (−)₂ havingthe opposite polarity at the terminal A₂ by means of a coupler, this isreferred to as crosstalk in the far ends, and when it generates acoupling signal (−)₂ having the same polarity at the terminal B₂, thisis referred to as crosstalk in the near ends.

In conventional differential couplers, only crosstalk in the near endsis used for communication, and crosstalk in the far ends is consumed asheat through the terminal resistor, and thus cannot be used forcommunication. Meanwhile, in the directional coupling differentialcommunication apparatus according to the embodiment of the presentinvention, crosstalk in the far ends between differential signals havinga polarity opposite to each other is also used, and therefore, thereceived signal can be increased.

Here, in the couplers, copper foil having a thickness of approximately20 μm formed on the two surfaces of a substrate and vias that penetratethrough the substrate are created through a printing process so thattransmission lines for the signal may be provided. The characteristicimpedance of the transmission lines is generally 50Ω but may have othervalues.

When the application for data communication between the display moduleand the motherboard in a portable phone is assumed, the communicationdistance (distance between couplers) is approximately 0.1 mm, but thesame structure can be used in the case where the distance is fromseveral mm to several cm.

Though a typical example relates to the connection between two modules,the number of modules may be three or more. The present invention alsoincludes a case of communication between three semiconductor chips ofwhich two semiconductor chips are mounted on the two surfaces of a PCBas shown in the below-described Example 15, for example, so that thetransmission lines that form a coupler provided on the PCB and thetransmission lines on the two semiconductor chips are coupled to eachother while the remaining semiconductor chip is connected to thetransmission lines provided on the PCB. In this case, semiconductorchips may be combined in any form, and as an example, a semiconductorchip connected to the transmission lines provided on a PCB can be amicroprocessor and the other semiconductor chips can be memory chips.

Here, in order to increase the coupling efficiency between the firstcoupler and the second coupler, a dielectric body in plate form may beinserted between the first coupler and the second coupler, which makeselectromagnetic field coupling possible even in the case where the firstcoupler and the second coupler have a gap that is relatively large.

In the case where a third coupler is provided on the first insulatingsubstrate so as to form a closed circuit, the first coupler and thethird coupler are respectively formed of two couplers and a terminalresistor for linking the two couplers so that a standing wave attenuatesand the flatness of the coupling degree can be maintained in thebroadband, which makes it possible to remove signal distortion.

Furthermore, the above-described first coupler and second coupler arecouplers in arc form having the same radius of curvature so that leadtransmission lines of the first module and the second module can be ledout at a free angle.

In this case, the center of the second coupler in the second modulematches with the center of the first coupler of the first module, andthe second module is provided so as to be rotatable relative to thefirst module, thereby making communication possible between theoperational members through electromagnetic field coupling.

In the case of couplers in arc form, the length of the arc of the secondcoupler may be shorter than the length of the arc of the first coupler,and thus, an excellent degree of coupling can be maintained even in thecase where the length of the arc of each coupler is not the same.

A third module having a third coupler, where an input/output connectionline is connected to a first end provided on a third insulatingsubstrate and either a ground line or an input/output connection line towhich an inverse signal of the signal inputted through the input/outputconnection line connected to the above-described first end is inputtedis connected to a second end, may further be provided, and the first tothird modules can be layered on top of each other so that the firstcoupler, the second coupler, and the third coupler at least partiallyoverlap as viewed in the direction in which the modules are layered ontop of each other, and signal coupling is generated between the firstcoupler, the second coupler, and the third coupler using capacitivecoupling and inductive coupling.

The three modules are layered on top of each other in this manner sothat the couplers overlap in the direction in which the modules arelayered on top of each other, and thus, a multi-drop bus can be formedusing any one module as a bus. As a result, simultaneous communicationbecomes possible between the module that works as a bus and the othertwo modules.

In the case where a third coupler is provided on the rear surface of thefirst insulating substrate, a third module with a third coupler may belayered in such a manner that the longitudinal direction of the firstcoupler crosses the longitudinal direction of the third coupler at rightangles so that electromagnetic interference between the first couplerand the third coupler can be prevented.

A second coupler in arc form, where an input/output connection line isconnected to a first end and either a ground line or an input/outputconnection line to which an inverse signal of the signal inputtedthrough the input/output connection line connected to theabove-described first end is inputted is connected to a second end, maybe built inside a first coupler in arc form, where an input/outputconnection line is connected to a first end provided on a firstinsulating substrate and either a ground line or an input/outputconnection line to which an inverse signal of the signal inputtedthrough the input/output connection line connected to theabove-described first end is inputted is connected to a second end, soas to be rotatable around the first coupler in a concentric manner, andthus, the couplers can work as an electromagnetic field connector in therotatable portion.

In this case, the first coupler and the second coupler typically form aconnector in the hinge of a housing that can be opened and closed as aelectromagnetic field connector in the rotatable portion.

In summary, the directional coupling communication apparatus accordingto the embodiment of the present invention can provide the followingworking effects:

1) A coupler where four signal lines and two terminal resistors arenecessary according to the prior art can be formed of two signal lines.

2) Since the number of lines for capacitive and inductive coupling istwo, it is relatively easy to match the coupling impedance as comparedto a conventional case where four signal lines are capacitively andinductively coupled to each other.

3) Signal reflection does not occur because matching termination can beachieved using a variable resistor provided in the transmitter/receivercircuit.

4) The signal is intensified through the crosstalk in the far ends, andtherefore, the reliability of communication increases.

5) Since (+) and (−) signals are always applied to the two ends of acoupler, the common signal does not change, making unnecessary radiation(noise) smaller.

Example 1

Next, the directional coupling differential communication apparatusaccording to Example 1 of the present invention is described inreference to FIGS. 7A to 9. FIGS. 7A and 7B are diagrams showing thestructure of the directional coupling differential communicationapparatus according to Example 1 of the present invention, where FIG. 7Ais a schematic perspective diagram which illustrates an example of theinterface realized between modules of the main substrate (motherboard)and a child substrate. For example, coupler components 41 ₁ and 41 ₂using FPCs 42 ₁ and 42 ₂ are installed on the main substrate 40 in amobile phone while coupler components 51 ₁ and 51 ₂ using FPCs 52 ₁ and52 ₂ are installed on the rear surface of the display module (childsubstrate) 50.

The coupler components 41 ₁, 41 ₂, 51 ₁, and 51 ₂ are respectivelyprovided with couplers 43 ₁, 43 ₂, 53 ₁, and 53 ₂, which arerespectively connected to transmitter/receiver circuits 46 and 56 vialead transmission lines 44 ₁, 44 ₂, 45 ₁, 45 ₂, 54 ₁, 54 ₂, 55 ₁, and 55₂. Here, terrace members 61 ₁ and 61 ₂ provided on the main substrate 40are used so that the couplers 43 ₁ and 43 ₂ provided on the couplercomponents 41 ₁ and 41 ₂ are installed in the proximity of the couplers53 ₁ and 53 ₂ provided in the coupler components 51 ₁ and 51 ₂ in thestructure. The main substrate 40 and the child substrate 50 are layeredon top of each other using a support member 62. In the followingexamples, including this example, the setting allows the couplingimpedance Z_(0-coupled) to be matched in the electromagnetic fieldcoupling between couplers that face each other.

FIGS. 8A to 9 are diagrams showing coupler components used in Example 1of the present invention, where FIG. 8A is a plan diagram showing thecoupler component provided on the main substrate side, FIG. 8B is a plandiagram showing the coupler component provided on the child substrateside, and FIG. 8C is a perspective plan diagram showing a case wherecoupler components are layered on top of each other with the one on thechild substrate side being inverted. In the coupler component 41, thecopper foil on one surface is patterned to form a coupler 43 and leadtransmission lines 44 and 45 while a plane 47 is formed on the othersurface.

The dimensions of the coupler 43 are different between the cases wherethe substrate is an FPC or a PCB and vary in accordance with thecommunication distance and the communication speed. An example can becited where the length is 5 mm and the width is 0.5 mm. In an example ofthe dimensions of the lead transmission lines 44 and 45, the width is0.3 mm, and close coupling can be achieved in places where two leadtransmission lines 44 and 45 are provided in close proximity with adistance that is three times or less greater than the width.

A differential signal is inputted to the two ends of the coupler on thetransmitter side while a differential signal is outputted from the twoends of the coupler on the receiver side. It is desirable for the leadtransmission lines for connecting the transmitter to the coupler and thelead transmission lines for connecting the coupler to the receiver tohave an equal length so that the delay of the signal is the same. Whenthe lead transmission lines 44 and 45 go out from the two ends of thecoupler 43 and are bent so as to return to the center of the coupler 43,the coupler 43 and the lead transmission lines 44 and 45 aresufficiently spaced away from each other, such as by approximately threetimes the width, in order to prevent capacitive and inductive coupling.In the case where the width of the coupler 43 is 0.5 mm and the width ofthe lead transmission lines 44 and 45 is 0.3 mm, for example, it isdesirable for them to be spaced away from each other by 1 mm to 1.5 mmor more.

In contrast, when the coupler 43 and the lead transmission lines 44 and45 are spaced away too far from each other, they are in coil form havingan inductance component which resonates with the parasitic capacitance.In the case where the band that can be used for communication isbroadened by making the resonant frequency sufficiently high, it iseffective to reduce the area surrounded by the coupler 43 and the leadtransmission lines 44 and 45 so that the inductance component becomessmaller. In the case where the coil is quadrangular, the inductance isdetermined by the shorter sides, and therefore, it is effective tonarrow down the distance between the coupler 43 and the leadtransmission lines 44 and 45.

In addition, the plane 47 provided on the surface on the opposite sidehas a missing portion 48 only in the portion that faces the coupler 43.As a result, the degree of coupling by the coupler 43 can be increased.In the case of a PCB, the substrate is thick, and this makes the effectsfrom the plane sufficiently small when the two couplers are placedsufficiently close to each other, and therefore, it is not necessary tocut out the plane on the side opposite to the couplers.

As shown in FIG. 8B, the coupler component provided on the childsubstrate side has the same shape as the coupler component shown in FIG.8A. In the case where the child substrate and the parent substrate arelayered on top of each other as shown in FIG. 8C, the two leadtransmission lines 44 and 45 or 54 and 55 are provided so as to be awayfrom each other and so as not to overlap in the direction in which thesubstrates are layered on top of each other in order to sufficientlyreduce the coupling between the lead transmission lines 44 and 45 orbetween the lead transmission lines 54 and 55.

FIG. 9 is a cross-sectional diagram showing the state where the childsubstrate and the parent substrate are layered on top of each other,where the surface layers 49 ₁, 49 ₂, 59 ₁, and 59 ₂ are provided forprotection on the two surfaces of the FPCs 42 and 52, which are placedso as to face each other with a gap in between. The width of the gap isfrom 0 mm to several cm. The substrates may be pasted to each other withan adhesive or the like so that the coupler 43 and the coupler 53overlap in the direction in which the substrates are layered on top ofeach other with an insulating film made of the same material as asurface layer of an FPC or polyethylene terephthalate (PET) in betweeninstead of having a gap.

FIG. 10 is a circuit diagram showing the transmitter/receiver circuitused in Example 1 of the present invention, where the upper side forms atransmitter circuit and the lower side forms a receiver circuit. Thetransmitter circuit transmits an NRZ (Non-Return to Zero) waveform.

Example 2

FIGS. 11A and 11B are diagrams illustrating the directional couplingdifferential communication apparatus according to Example 2 of thepresent invention. Here, only the difference from Example 1 isdescribed. FIG. 11A is a perspective diagram showing the terrace memberand its surroundings, and FIG. 11B is a cross-sectional diagram showingthe same as in FIG. 11A as viewed in the direction of the arrow. Asshown in the figures, the portions of the lead transmission lines 44 and45 of the coupler component 41 provided on the parent substrate side aremade to run along the sides of the terrace member 61 in close proximityto the connection portions.

Meanwhile, the lead transmission lines 54 and 55 of the couplercomponent 51 on the child substrate side are in the same state as inFIGS. 7A and 7B, and therefore, the direction in which the leadtransmission lines 44 and 45 run and the direction in which the leadtransmission lines 54 and 55 run are different. Accordingly, thedistance between the lead transmission lines 44 and 45 and the leadtransmission lines 54 and 55 increases, and thus, the degree of couplingbetween the two can be greatly reduced.

Example 3

Next, the directional coupling differential communication apparatusaccording to Example 3 of the present invention is described inreference to FIGS. 12A to 12C. FIGS. 12A to 12C are diagramsillustrating the coupler components for forming the directional couplingdifferential communication apparatus according to Example 3 of thepresent invention, where FIG. 12A is a plan diagram showing a couplercomponent provided on the main substrate side, FIG. 12B is a plandiagram showing a coupler component provided on the child substrateside, and FIG. 12C is a perspective plan diagram showing a case wherecoupler components are layered on top of each other with the one on thechild substrate side being inverted.

In Example 3, as shown in FIG. 12A or FIG. 12B, lead transmission lines44, 45, 54, and 55 are connected to an end of a side of the couplers 43and 53 along the long axis. This structure allows the lead transmissionlines 44 and 45 to be completely prevented from overlapping the leadtransmission lines 54 and 55 in the direction in which the couplercomponents are layered on top of each other in the case where thecoupler components 41 and 51 are layered on top of each other as shownin FIG. 12C, and thus, there is an advantage that the coupling betweenlead transmission lines can further be reduced.

Meanwhile, the place through which a current flows in close proximity tothe connection point between the coupler 43 or 53 and the leadtransmission lines 44, 45, 54, or 55 is different between the coupler 43and the coupler 53, and therefore, there is a possibility that theimpedance is not equal between an end and the center of the coupler 43or 53. Conversely, the effective width of the crossing portion is widerat the center of the crossing portion and narrower on the two sides, andtherefore, it is possible to make the band broader.

Example 4

Next, the directional coupling differential communication apparatusaccording to Example 4 of the present invention is described inreference to FIG. 13. FIG. 13 is a plan diagram showing a couplercomponent, where the coupler 43 ₃ is bent into a C shape so that the twoends of the coupler 43 ₃ come close to each other. Though in thefollowing description a case where the coupler 43 ₃ is bent twice into aC shape is cited, all the cases where the coupler 43 ₃ is bent so thatthe two ends come close to each other, including a case where the numberof times the coupler is bent is further increased, can be included inthe present example.

Thus, the coupler 43 ₃ can be bent so as to reduce the area occupied bythe coupler 43 ₃. In the case where the total length of the coupler 43 ₃is 5 mm, for example, the length L can be shortened to approximately 2.5mm by bending. Here, it is desirable for the distance S between the bentportions of the coupler 43 ₃ to be three times or more greater than thewidth W of the coupler 43 ₃ in order to prevent capacitive coupling andinductive coupling in the facing portions of the coupler 43 ₃. In thecase when W=0.5 mm, for example, S=1.5 mm, and therefore, the length ofthe center portion of the coupler 43 ₃ is 2.0 mm (=1.5 mm+0.5 mm×2),taking the length of the center line into consideration, and the lengthL of the side portions is 1.5 mm [=(5 mm−2 mm)/2]. Though the coupler onthe parent substrate side is described above, the coupler provided onthe child substrate side has the same structure, and thus, thesubstrates are layered on top of each other so that the couplers overlapcompletely.

In Example 4, it is easier to connect the lead transmission lines 44 and45, which are differential signal lines, to the coupler 43 ₃. That is tosay, when the lead transmission lines 44 and 45 that approach from thebottom in FIG. 13 are connected to the coupler 43 ₃, the coupler in Cshape can greatly reduce the indirect route portion, unlike the casewhere the coupler is linear as shown in Example 1 instead of being in aC shape, where the connection line to the lower terminal needs to havean indirect route because the differential signal lines connected to thetwo ends of the coupler should have the same wire length, and thedistance in the direction in which signals arrive is closer to the lowerterminal as compared to the upper terminal that is directly connected tothe coupler.

Example 5

Next, the directional coupling differential communication apparatusaccording to Example 5 of the present invention is described inreference to FIGS. 14A to 14C. FIGS. 14A to 14C are diagrams forillustrating the coupler components for forming the directional couplingdifferential communication apparatus according to Example 5 of thepresent invention, where FIG. 14A is a plan diagram showing a couplercomponent provided on the main substrate side, FIG. 14B is a plandiagram showing a coupler component provided on the child substrateside, and FIG. 14C is a perspective plan diagram showing a case wherecoupler components are layered on top of each other with the one on thechild substrate side being inverted.

As shown in FIG. 14A, the structure in Example 1 is adopted for thecoupler component 41 provided on the main substrate side. As shown inFIG. 14B, the structure in Example 3 is adopted for the couplercomponent 51 provided on the main substrate side. In addition, thelength of the coupler 43 is greater than the length of the coupler 53.

Thus, one coupler 43 is longer so that the other coupler 53 can beplaced anywhere in the range of this length, which reduces therestriction for positioning. Alternatively, the module can be moved whencommunication is achieved or communication can be achieved while themodule is moving. Here, the relationship of the difference between thelengths of the couplers may be opposite to each other. Likewise, thewidth of one coupler is greater so that the freedom for positioning canbe increased in the direction of the width.

Example 6

Next, the directional coupling differential communication apparatusaccording to Example 6 of the present invention is described inreference to FIGS. 15A to 15C. FIGS. 15A to 15C are diagramsillustrating the coupler components for forming the directional couplingdifferential communication apparatus according to Example 6 of thepresent invention, where FIG. 15A is a plan diagram showing the couplercomponent provided on the main substrate side, FIG. 15B is a plandiagram showing the coupler component provided on the child substrateside, and FIG. 15C is a perspective plan diagram showing a case wherethe coupler components are layered on top of each other with the one onthe child substrate side being inverted.

In Example 6, as shown in FIG. 15C, the coupler component 41 and thecoupler component 51 are formed so that the long axes of the coupler 43and the coupler 53 are not parallel when the coupler components arelayered on top of each other. When the couplers 43 and 53 having aconstant width and a uniform impedance cross diagonally, the width ofthe crossing portion is wide at the center of the crossing portion andnarrow at the two ends, and thus, a broadband is provided. Furthermore,the shape of the crossing portion is constant even when the location ofthe coupler 43 or 53 shifts in any direction on the plane relative tothe position of the other, and therefore, such effects can also begained that the coupling properties are constant irrespective of thepositional shifting of a module.

Thus, the couplers 43 and 53 are provided so as to cross each otherdiagonally in Example 6 of the present invention, and therefore, abroadband wireless communication path can be realized. In addition,there are such features that the properties of the communication path donot change even in the case where the location of the coupler component41 or the coupler component 51 is shifted relative to the other.

Example 7

Next, the directional coupling differential communication apparatusaccording to Example 7 of the present invention is described inreference to FIG. 16. FIG. 16 is a plan diagram showing the couplingstate of the coupler components for forming the directional couplingdifferential communication apparatus according to Example 7 of thepresent invention, where two couplers 43 ₁, 43 ₂, 53 ₁, 53 ₂ areprovided on each substrate, and the substrates are then layered on topof each other in the same manner as in FIGS. 7A and 7B.

In this case, the electromagnetic fields are generated in the orthogonaldirection along the coupler lines, and therefore, the couplers 43 ₁, 43₂, 53 ₁, 53 ₂ are arranged in the longitudinal direction of thecouplers, that is to say, in the direction of the line length. Thisarrangement makes interference between the couplers smaller, whichincreases reliability, and makes arrangement in close proximity possibleas shown in FIG. 16, and therefore, the density of the mounted elementscan be increased.

Example 8

Next, the directional coupling differential communication apparatusaccording to Example 8 of the present invention is described inreference to FIGS. 17A to 17C. FIGS. 17A to 17C are diagramsillustrating the coupler components for forming the directional couplingdifferential communication apparatus according to Example 8 of thepresent invention, where FIG. 17A is a plan diagram showing the couplercomponent provided on the main substrate side, FIG. 17B is a plandiagram showing the coupler component provided on the child substrateside, and FIG. 17C is a perspective plan diagram showing a case wherethe coupler components are layered on top of each other with the one onthe child substrate side being inverted.

In Example 8, semiconductor integrated circuit apparatuses 65 and 66having a transmitter/receiver circuit are connected to couplers 43 and53 using short bonding wires 63 ₁, 63 ₂, 64 ₁, and 64 ₂ instead of leadtransmission lines.

Example 9

Next, the directional coupling differential communication apparatusaccording to Example 9 of the present invention is described inreference to FIG. 18. FIG. 18 is a cross-sectional diagram showing thecoupler components and their surroundings for forming the directionalcoupling differential communication apparatus according to Example 9 ofthe present invention of which the basic structure is the same as thestructure shown in FIG. 9.

Here, the relative dielectric constant ε₁ of the gap between thecouplers (in the case where the gap is a space, the relative dielectricconstant is ε₀=1) is smaller than the dielectric constant ε₂ of theother parts around the coupler lines. For example, the relativedielectric constant of polyimide, which is the base resin of FPCs, is3.2, while the relative dielectric constant of the surface layer whereadditives are added to polyimide is 3.4. Meanwhile, the relativedielectric constant of air is 1.0 and the dielectric constant of PET is3.0. Accordingly, the gap between the two couplers 43 and 53 may be aspace or an intervening insulating film made of a material such as PETof which the relative dielectric constant is smaller than 3.2.

Thus, when the dielectric constant between the coupler lines is smallerthan the dielectric constant of the other parts surrounding the couplerlines, the crosstalk in the near ends becomes smaller and the crosstalkin the far ends becomes greater. The reason for this, as shown as FIG.5D, is that the propagating signal in the far ends due to an inductivecoupling current has a symbol opposite to that of the signal generatedthrough capacitive coupling, and thus, the signals are weakened by eachother, which in many cases results in, as shown in FIG. 5F, a negativesignal being propagated in the far ends. That is to say, crosstalk inthe far ends is a signal gained by subtracting a signal caused bycapacitive coupling from a signal caused by inductive coupling, andtherefore, the signal caused by capacitive coupling becomes smaller whenthe dielectric constant between the coupler lines is lowered, and thus,crosstalk in the far ends becomes greater.

In Example 9, as in the other examples, crosstalk in the far ends isalso used, and therefore, the reliability for communication can besecured. As a result, it is possible to leave a gap between two modules,for example, that are arranged in close proximity, and thus, there issuch an advantage that the connection between modules can be easilyachieved at a low cost. Alternatively, the selection of an insulatingfilm can be made wider when the modules are connected in close proximitywith the insulating film in between.

Example 10

Next, the directional coupling differential communication apparatusaccording to Example 10 of the present invention is described inreference to FIG. 19, where Example 10 relates to a transmitter/receivercircuit and the remaining structure is the same as in Examples 1 to 9.

FIG. 19 is a circuit diagram showing a transmitter/receiver circuit usedin the directional coupling differential communication apparatusaccording to Example 10 of the present invention, where connectionsbetween a number of terminal resistors that are aligned side-by-side arechanged by switches so that an impedance matching circuit of which theresistance value can be adjusted is provided on the input/outputterminal side.

Thus, an impedance matching circuit is provided on thetransmitter/receiver circuit side so that the resistor members fortermination connected to the couplers become unnecessary, and thus, thecosts can be lowered and the volume of the mounted parts can be reduced.In addition, the resistance value can be adjusted by means of thecircuit even in the case where the communication distance isinconsistent or the impedance of the couplers is inconsistent due to thepositional shift, and therefore, signal reflection can be suppressed. Inthe above-described prior art inventions, a resistor member is requiredfor termination and the impedance cannot be adjusted.

In addition, the impedance adjusting circuit can be implemented as adigital circuit as shown in FIG. 19 or can be implemented as an analogcircuit. When a received signal is inputted into the source of thetransistor instead of the gate as shown in FIG. 19, the input impedanceas viewed from the source can be changed through the application of abias to the gate of the transistor.

Example 11

Next, the directional coupling differential communication apparatusaccording to Example 11 of the present invention is described inreference to FIGS. 20 to 23B. FIG. 20 is a schematic diagram showing thestructure of the directional coupling differential communicationapparatus according to Example 11 of the present invention, where afirst module 70 and a second module 80 communicate with each other via athird module 90 in which two couplers 92 and 93 are provided.

In this case, the first module 70 and the second module 80 have the samestructure as the above-described child substrate, and thus arerespectively provided with the couples 72 and 82, which are connected tosemiconductor integrated circuit apparatuses 75 and 85 having atransmitter/receiver circuit through lead transmission lines 73, 74, 83,and 84.

Meanwhile, the third module 90 has two couplers 92 and 93, where thesetwo couplers 92 and 93 are connected through lead transmission lines 94and 95. Here, the lead transmission line 94 and the lead transmissionline 95 have the same length.

FIGS. 21A to 21C are schematic diagrams showing the structure of thedirectional coupling differential communication apparatus according toExample 11 of the present invention, where FIG. 21A is a plan diagramshowing the third module, FIG. 21B is a plan diagram showing the firstmodule and the second module, and FIG. 21C is a perspective plan diagramshowing a case where the first module and the second module are layeredon top of each other with one being inverted.

FIG. 22 is a cross-sectional diagram showing the structure in detail ofthe directional coupling differential communication apparatus accordingto Example 11 of the present invention, where an FR4 substrate 99, whichis a PCB substrate, is used as the substrate for the third module 90.Here, the rear surface of the FR4 substrate 99 is provided with a plane96 for electromagnetic shielding, and at the same time, surface layers97 and 98 are provided on the front and rear surfaces.

The couplers 72 and 82 and the lead transmission lines 73, 74, 83, and84 for forming the first module 70 and the second module 80 are formedusing wires on the PCB or FPC or wires on a substrate or a semiconductorchip within a package.

In this case, the first module 70 and the second module 80 achievecapacitive coupling and inductive coupling with the couplers 92 and 93provided in the third module 90 so that data communication can beestablished between the first module 70 and the second module 80.

FIGS. 23A and 23B are diagrams for illustrating a case where the firstmodule and the second module are formed of a semiconductor chip, whereFIG. 23A is a cross-sectional diagram showing a case where asemiconductor chip faces downward, and FIG. 23B is a cross-sectionaldiagram showing a case where a semiconductor chip faces upward.

As shown in FIG. 23A, in the case where the first module and the secondmodule are formed of semiconductor chips 77 and 87, the couplers 72 and82 are formed using wires in the semiconductor chips and are connectedto the third module 90 using bumps 78 and 88. In this case, the couplersface each other with a short distance in between without an interveningsemiconductor substrate, and therefore, the degree of coupling is great.

Meanwhile, as shown in FIG. 23B, in the case where the semiconductorchips 77 and 87 face upward, they are connected to the third module 90through bonding wires 79 and 89. In this case, the coupling isintervened by a semiconductor substrate, and therefore, the degree ofcoupling is slightly smaller.

Example 12

Next, the directional coupling differential communication apparatusaccording to Example 12 of the present invention is described inreference to FIG. 24. FIG. 24 is a cross-sectional diagram showing thedirectional coupling differential communication apparatus according toExample 12 of the present invention, where an FPC 91 is used as thesubstrate for the third module 90, and the first module 70 and thesecond module 80 are formed of semiconductor chips 77 and 87, and at thesame time, these semiconductor chips 77 and 87 are connected to a PCB100 through bonding wires 79 and 89. Here, an FR4 substrate 101 is usedfor the PCB 100, where a plane 102 is formed on the rear surface andsurface layers 103 and 104 are provided on the front and rear surfaces.In this case, in the same manner as in the case of FIG. 23A, coupling isachieved without an intervening semiconductor substrate.

Example 13

Next, the directional coupling differential communication apparatusaccording to Example 13 of the present invention is described inreference to FIGS. 25A to 25C. FIGS. 25A to 25C are schematic diagramsshowing the structure of the directional coupling differentialcommunication apparatus according to Example 13 of the presentinvention, where FIG. 25A is a plan diagram showing a third module, FIG.25B is a plan diagram showing a first module and a second module, andFIG. 25C is a perspective plan diagram showing a case where the firstmodule and the second module are layered on top of each other with onebeing inverted.

Example 13 corresponds to a case where the wires having the same lengthin Example 11 rearrange when the couplers 92 and 93 are shifted in thelateral direction. That is to say, no problem arises whenever wires aredrawn out as long as the lead transmission line 94 and the leadtransmission line 95 have the same length.

Example 14

Next, the directional coupling differential communication apparatusaccording to Example 14 of the present invention is described inreference to FIGS. 26A and 26B. FIGS. 26A and 26B are diagrams forillustrating the structure of the directional coupling differentialcommunication apparatus according to Example 14 of the presentinvention, where FIG. 26A is a plan diagram showing a third module, andFIG. 26B is a plan diagram showing a first module and a second module.

Example 14 corresponds to Example 4 shown in FIG. 13, and each coupler72, 82, 92, 93 is bent into a C shape. As shown in Example 11, in thecase where the couplers 72 and 82 are formed of wires in semiconductorchips, a problem arises in the case where the entire length of thecoupler 72 or 82 does not fit along one side of the chip. In the casewhere the entire length of the couplers 72 and 82 is 5 mm and one sideof the semiconductor chips is 4 mm, for example, the linear couplers 72and 82 cannot be formed of wires in the semiconductor chips. Even in thecase where one side of the semiconductor chips is greater than theentire length of the couplers 72 and 82, wires for connecting the twoends of the coupler 72 or 82 to the differential signal terminals of thetransmitter/receiver circuit 67 or 68 become long or do not have thesame wire length, and as a result, such a problem arises that the phaseof the differential signals is shifted from 180° the wires easily pickup noise.

Such a problem can be solved by bending the couplers 72 and 82 into ashape where the two ends approach each other as shown in FIGS. 26A and26B. In addition, wires can be made shorter for the connection to thetransmitter/receiver circuits 67 and 68, and therefore, wires havingprecisely the same length can be provided.

Example 15

Next, the directional coupling differential communication apparatusaccording to Example 15 of the present invention is described inreference to FIGS. 27 and 28. FIG. 27 is a schematic diagram showing thestructure of the directional coupling differential communicationapparatus according to Example 15 of the present invention, where afirst module 120, a second module 130, and a third module 140 arerespectively provided with semiconductor integrated circuit apparatuses124, 134, and 144 having a transmitter/receiver circuit and couplers121, 131, and 141 so as to establish communication between the firstmodule 120 and the second module 130 as well as between the first module120 and the third module 140.

In this case, in the first module 120 to the third module 140,respectively, the couplers 121, 131, and 141 and the semiconductorintegrated circuit apparatuses 124, 134, and 144 are connected throughlead transmission lines 122, 123, 132, 133, 142, and 143. Here, thesemiconductor integrated circuit apparatus 124 is a microprocessor whilethe semiconductor integrated circuit apparatuses 134 and 144 aresemiconductor memory apparatuses (memories).

FIG. 28 is a cross-sectional diagram showing the structure in detail ofthe directional coupling differential communication apparatus accordingto Example 15 of the present invention, where an FR4 substrate 125,which is a PCB substrate, is used as the substrate for the first module120. Here, the front surface of the FR4 substrate 125 is provided with asurface layer 126.

In the second module 130, the coupler 131 is layered on the frontsurface side so as to overlap the coupler 121 in the first module 120 inthe direction in which the modules are layered on top of each other.Meanwhile, the third module 140 is layered on the rear surface side sothat the coupler 141 overlaps the coupler 121 in the first module 120 inthe direction in which the modules are layered on top of each other.

In this case, in order for communication to be achieved with only onememory (134, 144), the other memory (144, 134) recognizes this and mayignore the contents of the communication. Meanwhile, each memory (134,144) communicates with a microprocessor (124) individually in timedivision.

In Example 15, the coupler 121 is on the front surface of the FR4substrate 125, and therefore, the distance between the coupler 121 and131 is shorter than the distance between the coupler 121 and the coupler141, and thus, the degree of coupling between the coupler 121 and thecoupler 131 is stronger than the degree of coupling between the coupler121 and the coupler 141. However, the coupler 121 may be formed of wiresinside the FR4 substrate 125 by using a multilayer wire substrate as theFR4 substrate 125 so that the distance between the coupler 121 and thecoupler 131 is approximately equal to the distance between the coupler121 and the coupler 141, and thus, the degree of coupling between thecoupler 121 and the coupler 131 may be approximately equal to the degreeof coupling between the coupler 121 and the coupler 141.

Example 16

Next, the directional coupling differential communication apparatusaccording to Example 16 of the present invention is described inreference to FIGS. 29 and 30. FIG. 29 is a schematic diagram showing thestructure of the directional coupling differential communicationapparatus according to Example 16 of the present invention, where afirst module 150, a second module 130, and a third module 140 arerespectively provided with semiconductor integrated circuit apparatuses154, 134, and 144 having a transmitter/receiver circuit and couplers 151₁, 151 ₂, 131, and 141 so as to establish communication between thefirst module 150 and the second module 130 as well as between the firstmodule 150 and the third module 140.

In this case, in the first module 150, the two couplers 151 ₁ and 151 ₂are connected in series through a connection transmission line 155 andare connected to the semiconductor integrated circuit apparatus 154through lead transmission lines 152 and 153.

In the second module 130 and the third module 140, as in Example 15, thecouplers 131 and 141 and the semiconductor integrated circuitapparatuses 134 and 144 are respectively connected to each other throughlead transmission lines 132, 133, 142, and 143. Here as well, thesemiconductor integrated circuit apparatus 154 is a microprocessor whilethe semiconductor integrated circuit apparatuses 134 and 144 aresemiconductor memory apparatuses (memories).

FIG. 30 is a cross-sectional diagram showing the structure in detail ofthe directional coupling differential communication apparatus accordingto Example 16 of the present invention, where an FR4 substrate 156,which is a PCB substrate, is used as the substrate for the first module150. Here as well, the rear surface of the FR4 substrate 156 is providedwith a plane 157 for electromagnetic shielding, and at the same time,the front and the rear surfaces are provided with surface layers 158 and159.

The second module 130 is layered on the first module so that the coupler131 overlaps the coupler 151 ₁ in the first module 150 in the directionin which the two modules are layered on top of the other module.Meanwhile, the third module 140 is layered on the first module so thatthe coupler 141 overlaps the coupler 151 ₂ in the first module 150 inthe direction in which the two modules are layered on top of the othermodule.

In this case as well, as in Example 15, the microprocessor (154) cancommunicate with the two memories (134, 144) simultaneously, and eachmemory (134, 144) communicates with the microprocessor (154) in timedivision. Here, signals attenuate in the couplers and the signal lengthis different between the transmitter/receiver provided inside thesemiconductor circuit apparatuses 154, 134, and 144 and the couplers 151₁, 151 ₂, 131, and 141, and therefore, the amplitude and the phase ofthe differential signal inputted into the two ends of each coupler 151₁, 151 ₂, 131, and 141 are shifted, and thus, the signal transmissionperformance is inferior to the case where there is only one coupler.

Though in the figures the first module 150 is provided with two couplers151 ₁ and 151 ₂, three or more couplers may be provided, and in thiscase, it is possible to couple modules of which the number correspondsto the number of couplers. Here, the greater the number of couplers is,the more the signal transmission performance deteriorates.

Example 17

Next, the directional coupling differential communication apparatusaccording to Example 17 of the present invention is described inreference to FIGS. 31 and 32. FIG. 31 is a schematic diagram showing thestructure of the directional coupling differential communicationapparatus according to Example 17 of the present invention, where afirst module 160, a second module 130, and a third module 140 arerespectively provided with semiconductor integrated circuit apparatuses164, 134, and 144 having a transmitter/receiver circuit and couplers161, 131, and 141 so as to establish communication between the firstmodule 160 and the second module 130 as well as between the first module160 and the third module 140.

In this case, the first module 160 has such a length as to be able todeal with two couplers 131 and 141 and is connected to the semiconductorintegrated circuit apparatus 164 through lead transmission lines 162 and163. In the second module 130 and the third module 140, as in Example15, the couplers 131 and 141 and the semiconductor integrated circuitapparatuses 134 and 144 are respectively connected to each other throughlead transmission lines 132, 133, 142, and 143. Here as well, thesemiconductor integrated circuit apparatus 164 is a microprocessor whilethe semiconductor integrated circuit apparatuses 134 and 144 aresemiconductor memory apparatuses (memories).

FIG. 32 is a cross-sectional diagram showing the structure in detail ofthe directional coupling differential communication apparatus accordingto Example 17 of the present invention, where an FR4 substrate 165,which is a PCB substrate, is used as the substrate for the first module160. Here as well, the rear surface of the FR4 substrate 165 is providedwith a plane 166 for electromagnetic shielding, and at the same time,the front and the rear surfaces are provided with surface layers 167 and168.

The second module 130 is layered on the first module so that the coupler131 overlaps a portion of the coupler 161 in the first module 160 in thedirection in which the two modules are layered on top of the othermodule. Meanwhile, the third module 140 is layered on the first moduleso that the coupler 141 overlaps the other portion of the coupler 161 inthe first module 160 in the direction in which the two modules arelayered on top of the other module.

In this case as well, as in Example 16, the microprocessor (164) cancommunicate with the two memories (134, 144) simultaneously, and eachmemory (134, 144) communicates with the microprocessor (164) in timedivision. Here, signals attenuate in the couplers 151 ₁ and 151 ₂ andthe signal length is different between the transmitter/receiver providedinside the semiconductor circuit apparatuses 164, 134, and 144 and thecouplers 161, 131, and 141, and therefore, the amplitude and the phaseof the differential signal inputted into the two ends of each coupler161, 131, and 141 are shifted, and thus, the signal transmissionperformance is inferior.

Though in the figures the coupler 161 in the first module 160 has such alength as to deal with two couplers, it may have such a length as todeal with three or more couplers. In such a case, it is possible tocouple modules of which the number corresponds to the length of thecoupler. The greater the number of couplers is, the more the signaltransmission performance deteriorates.

Example 18

Next, the directional coupling differential communication apparatusaccording to Example 18 of the present invention is described inreference to FIGS. 33A to 37C. FIGS. 33A to 33C are diagrams forillustrating the structure of the modules for forming the directionalcoupling differential communication apparatus according to Example 18 ofthe present invention, where FIG. 33A is a plan diagram showing a firstmodule, FIG. 33B is a plan diagram showing a second module, and FIG. 33Cis a perspective plan diagram showing a case where the two modules arelayered on top of each other with the second module being inverted.

As shown in FIG. 33A or 33B, in each module 110 ₁ or 110 ₂, a coupler112 ₁ or 112 ₂ is formed on an FPC 111 ₁ or 111 ₂ and a leadtransmission line 113 ₁ or 113 ₂ is connected to one end of the coupler112 ₁ or 112 ₂, and at the same time, the other end is connected to atermination line 114 ₁ or 114 ₂. Here, a plane 115 ₁ or 115 ₂ isprovided on the rear surface of the FPC 111 ₁ or 111 ₂, and a missingportion 116 ₁ or 116 ₂ of the plane is provided in a portion that facesthe coupler 112 ₁ or 112 ₂.

Next, the operational principle of Example 18 according to the presentinvention is described in reference to FIGS. 34A to 37C, which isbasically the same as the operational principle described in referenceto FIGS. 4A to 6D. First, as shown in FIG. 34A, the input end of thecoupler 112 ₁ for the (+)₁ signal is terminal A₁, and the connectionpoint of the coupler 112 ₁ with the termination line 114 ₁ is terminalB₁. Likewise, the output end of the coupler 112 ₁ for a signal isterminal A₂, and the connection point of the coupler 112 ₁ with thetermination line 114 ₂ is terminal B₂.

FIG. 34B is a diagram showing a waveform of an example of the (+)₁signal, and FIG. 34C is a diagram showing a waveform of the wavereflected from the terminal B₁. The terminal B₁ is connected to thetermination line 114 ₁ so as to be grounded to the termination potential(V_(T)), and therefore, the potential of the terminal B₁ is always thetermination potential (V_(T)), which does not change. Accordingly, whenthe (+)₁ signal reaches the terminal B₁, a waveform having the oppositepolarity is formed as a reflected wave in such a manner that thepotential of the terminal B₁ is constant and progresses towards theterminal A₁. In this case, the reflected wave is generated after thetime TD has elapsed before the (+)₁ signal reaches the terminal B₁.

When the (+)₁ signal propagates from the terminal A₁ of the coupler 112₁ toward the terminal B₁, a capacitive coupling current and an inductivecoupling current are induced and flow through the coupler 112 ₂ due tothe coupling effects of i=C(dv/dt) and v=L(di/dt) in exactly the samemanner as the operational principle described in reference to FIGS. 4Ato 6D, and the waveform of the capacitive coupling signal shown in FIG.35A appears in the terminal A₂. In addition, the capacitive couplingsignal shown in FIG. 35B appears in the terminal B₂.

Meanwhile, the inductive coupling current has the waveform shown in FIG.35C in exactly the same manner as the operational principle described inreference to FIGS. 4A to 6D and has the waveform shown in FIG. 35E whenoverlapping the capacitive coupling signal.

In addition, the signal that appears in the terminal B₂ has a symbolopposite to that of the signal that appears in the terminal B₂ due tothe capacitive coupling as shown in FIG. 35D so as to weaken each other,and as a result, in many cases, a negative signal propagates through theterminal B₂ as shown in FIG. 35F.

Meanwhile, the wave reflected from the terminal B₁ generates a couplingsignal of the reflected wave having the opposite polarity as shown inFIG. 36A in the terminal A₂ and a coupling signal having the samepolarity as shown in FIG. 36B in the terminal B₂ due to the sameprinciple as the operational principle described in reference to FIGS.4A to 6D. Here, the coupling signal appears in the terminal A_(z) afterthe time 2TD, which is required for the (+)₁ signal to have a roundtripthrough the coupler 112 ₁, has elapsed. The coupling signal appears inthe terminal B₂ at the same time as the reflection starts from theterminal B₁, which requires time TD.

Accordingly, the coupling signal shown in FIG. 35E and the couplingsignal shown in FIG. 36A overlap so as to generate the signal in FIG.36C in the terminal A₂. Likewise, the coupling signal shown in FIG. 35Fand the coupling signal shown in FIG. 36B overlap so as to generate thesignal in FIG. 36D in the terminal B₂.

The coupling signal that has reached the terminal B₂ as shown in FIG.36D becomes a reflected wave having the opposite polarity because theterminal B₂ is connected and short-circuited to the terminal line 114 ₂and appears in the terminal A₂ as the waveform shown in FIG. 37A. Thesignal due to this reflected wave delays by TD, which is the time forpropagation through the coupler 112 ₂, and delays by 2TD as a whole.

Accordingly, the waveform shown in FIG. 37A and the waveform shown inFIG. 37B that corresponds to FIG. 36C overlap so that the waveform shownin FIG. 37C appears in the terminal A₂. Therefore, in Example 18 aswell, the coupling signal that appears in the terminal B₂ andcorresponds to the crosstalk in the far ends is used for communication,and thus, the reliability of the signal transmission can be increased.

When the length of the couplers 112 ₁ and 112 ₂ in FIG. 34A is half ofthe length of the couplers 12 ₁ and 12 ₂ in FIG. 4A, the time for thewaveform described in reference to FIGS. 35A to 37C to reach from oneend of the coupler to the other is TD/2, and the time required for theroundtrip is TD. Accordingly, 2TD in FIG. 37C is halved, which is TD,and therefore, the waveform in FIG. 37C becomes equal to the waveform inFIG. 6C. That is to say, the coupler in Example 18 has a length that ishalf of that of the coupler in Example 1 in order for the same signal tocommunicate, and thus, the coupler can be made smaller. Here, this is asingle-end signal instead of a differential signal, and therefore, theresistance to the same phase noise is lowered.

Example 19

Next, the directional coupling differential communication apparatusaccording to Example 19 of the present invention is described inreference to FIGS. 38A and 38B, which is an example of the improveddirectional coupling differential communication apparatus of Example 1.FIGS. 38A and 38B are diagrams for illustrating the structure of thedirectional coupling differential communication apparatus according toExample 19 of the present invention, where FIG. 38A is a schematicperspective diagram and FIG. 38B is a schematic side diagram. Here, acoupler is directly provided on the surface of a child substrate inorder to realize the interface between modules of a main substrate(motherboard) and the child substrate.

As in Example 1, coupler components 41 ₁ and 41 ₂ using an FPC 42 ₁ or42 ₂ are installed on a main substrate 40, and each coupler component 41₁ or 41 ₂ is provided with a coupler 43 ₁ or 43 ₂, which is connected toa transmitter/receiver circuit 46 via lead transmission lines 44 ₁ or 44₂ and 45 ₁ or 45 ₂.

Meanwhile, couplers 53 ₁ and 53 ₂ are directly provided on the surfaceof the display module (child substrate) 50 and are connected to atransmitter/receiver circuit 56 via lead transmission lines 54 ₁, 54 ₂,55 ₁, and 55 ₂. Here, a terrace member 61 ₁ or 61 ₂ provided on the mainsubstrate 40 is used so that the coupler 43 ₁ or 43 ₂ provided in thecoupler component 41 ₁ or 41 ₂ is installed in close proximity to thecoupler 53 ₁ or 53 ₂ provided on the child substrate 50 in thestructure. The main substrate 40 and the child substrate 50 are layeredon top of each other using a support member 62. Here as well, thesetting allows the coupling impedance Z_(0-coupled) to be matched in theelectromagnetic field coupling between the couplers that face eachother.

Thus, in Example 19 of the present invention, wires on the childsubstrate can form couplers and lead transmission lines, which makes anFPC unnecessary and a reduction in the cost possible. Though it isnecessary for the FPC to be bent with a small curvature radius inExample 1, no FPC is used in Example 19 where the manufacturing processcan be simplified.

Example 20

Next, the directional coupling differential communication apparatusaccording to Example 20 of the present invention is described inreference to FIGS. 39A and 39B, which is an example of the improveddirectional coupling differential communication apparatus of Example 19.FIGS. 39A and 39B are diagrams for illustrating the structure of thedirectional coupling differential communication apparatus according toExample 20 of the present invention, where FIG. 39A is a schematicperspective diagram and FIG. 39B is a schematic side diagram. Here,couplers are directly provided on the surface of a parent substrate anda child substrate, and at the same time, a dielectric body is used tostrengthen the electromagnetic field coupling in order to realize theinterface between modules of the main substrate (motherboard) and thechild substrate.

Couplers 43 ₁ and 43 ₂ are directly provided on the surface of a mainsubstrate 40 and are connected to a transmitter/receiver circuit 46 vialead transmission lines 44 ₁, 44 ₂, 45 ₁, and 45 ₂. Meanwhile, couplers53 ₁ and 53 ₂ are directly provided on the surface of a display module(child substrate) 50 and are connected to a transmitter/receiver circuit56 via lead transmission lines 54 ₁, 54 ₂, 55 ₁, and 55 ₂.

Here, a dielectric body 69 ₁ or 69 ₂, such as dielectric ceramics madeof a material of which the relative dielectric constant is higher than1, for example, BaO—R₂O₂—TiO₂, is provided between the coupler 43 ₁ or43 ₂ and the coupler 53 ₁ or 53 ₂ so as to strengthen theelectromagnetic field coupling between the coupler 43 ₁ or 43 ₂ and thecoupler 53 ₁ or 53 ₂. The main substrate 40 and the child substrate 50are layered on top of each other using a support member 62. Here aswell, the setting allows the coupling impedance Z_(0-coupled) to bematched in the electromagnetic field coupling between the couplers thatface each other.

Thus, in Example 20 of the present invention, wires on the parentsubstrate and the child substrate can form couplers and leadtransmission lines, which makes a terrace member and an FPC unnecessaryas well as a reduction in the cost possible. Though it is necessary forthe FPC to be bent with a small curvature radius in Example 1, no FPC isused in Example 20 where the manufacturing process can be simplified.

Example 21

Next, the directional coupling differential communication apparatusaccording to Example 21 of the present invention is described inreference to FIGS. 40 to 41C, which is an example of the improveddirectional coupling differential communication apparatus of Example 11.That is to say, in Example 11, it can be seen from the results ofelectromagnetic field simulation that a stationary wave exists withinthe closed circuit shown in FIG. 21A, and the signal distorts in thecase where the couplers 92 and 93 are long.

FIG. 40 is a graph for illustrating the results of electromagnetic fieldsimulation, where flat characteristics are gained in the case where thelength L of the couplers is 2.5 mm while a bump appears in the degree ofcoupling so that the flatness is lost in the cases where the length is5.0 mm, 7.5 mm, and 10.0 mm. The peak values in the cases of L=5.0 mm,7.5 mm, and 10.0 mm are 0.638 dB at 7.000 GHz, 0.699 dB at 5.100 GHz,and 0.673 dB at 4.050 GHz.

FIGS. 41A to 41C are schematic diagrams showing the structure of thedirectional coupling differential communication apparatus according toExample 21 of the present invention, where FIG. 41A is a plan diagramshowing a third module, FIG. 41B is a plan diagram showing a firstmodule and a second module, and FIG. 41C is a perspective plan diagramshowing a case where the first module and the second module are layeredon top of each other with one being inverted.

In Example 21, as shown in FIG. 41A, two couplers provided in the thirdmodule 90 are respectively formed of two couplers 92 ₁ and 92 ₂ or twocouplers 93 ₁ and 93 ₂ and a terminal resistor 92 ₃ or 93 ₃ that linksthe two couplers. Here, the lead transmission line 94 and the leadtransmission line 95 have the same length. The resistor value of theterminal resistor 92 ₃ or 93 ₃ is matched to the characteristicimpedance of the lead transmission line 94 and the lead transmissionline 95.

Here, the first module 70 and the second module 80 are the same as inExample 11 and are provided with couplers 72 and 82, respectively, andare connected to a semiconductor integrated circuit apparatus having atransmitter/receiver circuit through lead transmission lines 73, 74, 83,and 84.

Thus, in Example 21 of the present invention, a terminal resistor isinserted into a closed circuit so as to terminate the signal formatching so that the stationary wave attenuates, making it possible toremove signal distortion.

Example 22

Next, the directional coupling differential communication apparatusaccording to Example 22 of the present invention is described inreference to FIGS. 42A to 42C, and Example 22 is an example of theimproved directional coupling differential communication apparatus ofExample 13. That is to say, in Example 13 as in Example 11, it can beseen that a stationary wave exists within a closed circuit that forms athird module, and a signal is distorted in the case where couplers 92and 93 are long.

FIGS. 42A to 42C are schematic diagrams showing the directional couplingdifferential communication apparatus according to Example 22 of thepresent invention, where FIG. 42A is a plan diagram showing a thirdmodule, FIG. 42B is a plan diagram showing a first module and a secondmodule, and FIG. 42C is a perspective plan diagram showing a case wherethe first module and the second module are layered on top of each otherwith one being inverted.

In Example 22, as shown in FIG. 42A, two couplers provided in a thirdmodule 90 are respectively formed of two couplers 92 ₁ and 92 ₂ or twocouplers 93 ₁ and 93 ₂ as well as a terminal resistor 92 ₃ or 93 ₃ forlinking the two couplers. Here, the lead transmission line 94 and thelead transmission line 95 have the same length. The resistor value ofthe terminal resistor 92 ₃ or 93 ₃ is matched to the characteristicimpedance of the lead transmission line 94 and the lead transmissionline 95.

Here, the first module 70 and the second module 80 are the same as inExample 13 and are provided with couplers 72 and 82, respectively, andare connected to a semiconductor integrated circuit apparatus having atransmitter/receiver circuit through lead transmission lines 73, 74, 83,and 84.

Thus, in Example 22 of the present invention as well, a terminalresistor is inserted into a closed circuit so as to terminate the signalfor matching so that the stationary wave attenuates, making it possibleto remove signal distortion.

Example 23

Next, the directional coupling differential communication apparatusaccording to Example 23 of the present invention is described inreference to FIGS. 43A and 43B, and Example 23 is an example of theimproved directional coupling differential communication apparatus ofExample 14. That is to say, in Example 14 as in Example 11, it can beseen that a stationary wave exists within a closed circuit that forms athird module, and a signal is distorted in the case where couplers 92and 93 are long.

FIGS. 43A and 43B are schematic diagrams showing the directionalcoupling differential communication apparatus according to Example 23 ofthe present invention, where FIG. 43A is a plan diagram showing a thirdmodule and FIG. 43B is a plan diagram showing a first module and asecond module.

In Example 23, as shown in FIG. 43A, two couplers provided in a thirdmodule 90 are respectively formed of two couplers 92 ₁ and 92 ₂ or twocouplers 93 ₁ and 93 ₂ as well as a terminal resistor 92 ₃ or 93 ₃ forlinking the two couplers. Here, the lead transmission line 94 and thelead transmission line 95 have the same length. The resistor value ofthe terminal resistor 92 ₃ or 93 ₃ is matched to the characteristicimpedance of the lead transmission line 94 and the lead transmissionline 95.

Here, the first module 70 and the second module 80 are the same as inExample 14 and are provided with couplers 72 and 82, respectively, andare connected to transmitter/receiver circuits 67 and 68, respectively,through lead transmission lines 73, 74, 83, and 84.

Thus, in Example 23 of the present invention, couplers provided in aclosed circuit are formed of two couplers and a terminal resistor forlinking the two couplers, and therefore, the properties of the degree ofcoupling can be flattened in the same manner as in Example 21 or Example22, and as a result, signal distortion can be removed.

Example 24

Next, the directional coupling differential communication apparatusaccording to Example 24 of the present invention is described inreference to FIG. 44. In Example 24, the first module 70 and the secondmodule 80 in the directional coupling differential communicationapparatus in Example 11 are formed of a package, and the remaining partof coupling state between couplers is the same as in Example 11.

FIG. 44 is a schematic cross-sectional diagram showing the structure ofthe directional coupling differential communication apparatus accordingto Example 24 of the present invention, where a semiconductor integratedcircuit chip is mounted inside a package.

In the case where the first module and the second module are formed of apackage 170 ₁ or 170 ₂ as shown in FIG. 44, a coupler 172 ₁ or 172 ₂ isformed using the wires of the package 170 ₁ or 170 ₂ and is connected toa third module 90 using bumps 174 ₁ or 174 ₂ formed on the rear surfaceof the substrate 171 ₁ or 171 ₂.

In Example 24 of the present invention, a coupler can be made of wiresof a package, and therefore, first and second modules can be providedcloser to a coupler end of the third module than in the case where acoupler is made of wires on a semiconductor chip, and thus, the degreeof coupling can be strengthened. Though the couplers are formed of wireson the substrates 171 ₁ and 171 ₂ on the side where the semiconductorchips are mounted in the figure, the couplers may be formed of wires onthe substrates 171 ₁ and 171 ₂ on the rear side.

Example 25

Next, the directional coupling differential communication apparatusaccording to Example 25 of the present invention is described inreference to FIGS. 45 to 46C. In Example 25, the design of thedirectional coupling differential communication apparatus of Example 15is changed in order for it to be used as a multi-drop bus.

FIG. 45 is a diagram for illustrating the directional couplingdifferential communication apparatus according to Example 25 of thepresent invention, where coupler components 180 ₁, 180 ₂, and 180 ₃ aremounted on top of each other to form a multi-drop bus. In each couplercomponent 180 ₁, 180 ₂, or 180 ₃, a coupler 182 ₁, 182 ₂, or 182 ₃ isprovided on the surface of an FPC 181 ₁, 181 ₂, or 181 ₃ and isconnected to lead transmission lines 183 ₁ and 184 ₁, 183 ₂ and 184 ₂,or 183 ₃ and 184 ₃. In addition, a plane 185 ₁, 185 ₂, or 185 ₃ having amissing portion 186 ₁, 186 ₂, or 186 ₃ in a portion corresponding to thecoupler 182 ₁, 182 ₂, or 182 ₃ is provided on the rear surface of theFPC 181 ₁, 181 ₂, or 181 ₃.

In addition, the two surfaces, front and rear, of the FPCs 181 ₁, 181 ₂,or 181 ₃ are provided with surface layers 187 ₁ and 188 ₁, 187 ₂ and 188₂, or 187 ₃ and 188 ₃ for protection, and the FPCs face each other witha gap in between. The distance of the gaps is 0 mm to several cm.Instead of the gaps, insulating films made of a material of the surfacelayers of the FPCs, such as polyethylene terephthalate (PET), issandwiched between the FPCs, which are thus pasted together with anadhesive so that the couplers 182 ₁, 182 ₂, and 182 ₃ overlap in thedirection in which the FPCs are layered on top of each other. Inaddition, there are no restrictions to the FPCs, but rather printedcircuit boards (PCBs), semiconductor substrates, or substrates within apackage may be used.

FIGS. 46A to 46C are diagrams for illustrating the direction in whichlead transmission lines are led, where FIG. 46A is a plan diagramshowing a coupler component 180 ₁ located in a lower layer and a couplercomponent 180 ₃ located in an upper layer, FIG. 46B is a plan diagramshowing a coupler component 180 ₂ located in a middle layer, and FIG.46C is a partial perspective plan diagram showing a case where thecomponents are layered as in FIG. 45. Here, the directions in which thelead transmission lines 183 ₁, 184 ₁, 183 ₃, and 184 ₃ are led out fromthe upper and lower coupler components 180 ₁ and 180 ₃ are opposite tothe directions in which the lead transmission lines 183 ₂ and 184 ₂ areled out from the coupler component 180 ₂ in the middle layer so that thecoupling between the lead transmission lines can be reduced.

In Example 25 of the present invention, the three couplers are layeredon top of each other in the direction in which the coupler componentsare layered on top of each other, and therefore, a multi-drop bus can beformed using the middle coupler component 180 ₂ as the bus so that thecoupler 182 ₂ can communicate with the coupler 182 ₁ and the coupler 182₃ simultaneously. It is also possible to form a multi-drop bus using thelower coupler component 180 ₁ as the bus so that the coupler 182 ₁ cancommunicate with the coupler 182 ₂ and the coupler 182 ₃ simultaneously.

Example 26

Next, the directional coupling differential communication apparatusaccording to Example 26 of the present invention is described inreference to FIGS. 47A to 47C. FIGS. 47A to 47C are schematic diagramsshowing the structure of the directional coupling differentialcommunication apparatus according to Example 26 of the presentinvention, where FIG. 47A is a plan diagram showing a third module fromthe top, FIG. 47B is a plan diagram showing the third module from thebottom, and FIG. 47C is a perspective plan diagram showing the mainportion of the third module. As shown in FIG. 47C, the couplers 191 ₁and 191 ₂ provided on the front and rear surfaces of an insulatingsubstrate 190 are placed in the directions perpendicular to each otherso that interference between the couplers 191 ₁ and 191 ₂ can beprevented. The symbols 192 ₁, 192 ₂, 193 ₁, and 193 ₂ in the figures arelead transmission lines. The symbols 194 ₁, 194 ₂, 195 ₁, and 195 ₂ inthe figures are planes and missing portions of the planes.

Accordingly, the coupler 191 ₁ and the coupler in the first module canbe coupled, and the coupler 191 ₂ and the coupler in the second modulecan be coupled without causing coupling between the first module and thesecond module, and therefore, no crosstalk occurs.

Example 27

Next, the directional coupling differential communication apparatusaccording to Example 27 of the present invention is described inreference to FIGS. 48A to 49C, where Example 27 is a modification ofExample 1. FIGS. 48A to 48C are schematic diagrams showing the structureof the directional coupling differential communication apparatusaccording to Example 27 of the present invention, where FIG. 48A is aplan diagram showing a coupler component in a first module, FIG. 48B isa plan diagram showing a coupler component in a second module, and FIG.48C is a perspective plan diagram showing a case where the modules arelayered on top of each other with the second module being inverted fromthe front to the rear side.

In Example 27, as shown in FIG. 48A, a coupler 43 provided in a couplercomponent 41 in a first module is a coupler in arc form. As shown inFIG. 48B, a coupler 53 provided in a coupler component 51 in a secondmodule is also a coupler in arc form that is the same shape as of thecoupler 43. As shown in FIG. 48C, the modules are layered on top of eachother with the second module being in a rotated state by an angle θ.Though the second module is inverted from the front to the rear sidewhen layered, it may be layered without being inverted.

FIGS. 49A to 49C are graphs illustrating the dependency of the degree ofcoupling on the angle θ, where FIG. 49A is a graph illustrating thedegree of coupling in the case of θ=0°, FIG. 49B is a graph illustratingthe degree of coupling in the case of θ=90°, and FIG. 49C is a graphillustrating the degree of coupling in the case of θ=180°. As shown inthe figures, it can be seen from the electromagnetic field simulationthat stable degrees of coupling can be gained between θ=0° and θ=180°.

Accordingly, lead transmission lines 44, 45, 54, and 55 in the firstmodule and in the second module can be led out at a free angle, whichcan increase the freedom in design. Here, the lead transmission linescan be installed so as to be freely rotatable relative to the firstmodule and the second module so as to be used as an electromagneticfield coupling connector in a rotatable portion.

Example 28

Next, the directional coupling differential communication apparatusaccording to Example 28 of the present invention is described inreference to FIGS. 50A to 50C, and Example 28 is a modification ofExample 27. FIGS. 50A to 50C are schematic diagrams showing thestructure of the directional coupling differential communicationapparatus according to Example 28 of the present invention, where FIG.50A is a plan diagram showing a coupler component in a first module,FIG. 50B is a plan diagram showing a coupler component in a secondmodule, and FIG. 50C is a perspective plan diagram showing a case wherethe modules are layered on top of each other. Though the second moduleis inverted from the front to the rear side when layered, it may belayered without being inverted.

In Example 28, as shown in FIG. 50A, a coupler 43 provided in a couplercomponent 41 in the first module is a coupler in arc form that is almostcircular as in Example 27. Meanwhile, as shown in FIG. 50B, a coupler 53provided in a coupler component 51 in the second module is a coupler inarc form that is in a crescent shape.

As shown in FIG. 50C, at whichever angle θ the couplers are coupled whenone coupler is in a coupler in arc form that is in a crescent shape, thedegree of coupling barely varies, and therefore, an electromagneticfield coupling connector to be used in a rotatable portion can beprovided.

Example 29

Next, the directional coupling differential communication apparatusaccording to Example 29 of the present invention is described inreference to FIGS. 51A to 51C. FIGS. 51A to 51C are schematic diagramsshowing the structure of the directional coupling differentialcommunication apparatus according to Example 29 of the presentinvention, which is appropriate as an electromagnetic field couplingconnector to be used in a rotatable portion. FIG. 51A is a partialperspective diagram showing the main portion of the apparatus, and FIGS.51B and 51C are perspective diagrams showing an electromagnetic fieldcoupling connector.

As shown in FIG. 51A, a coupler 204 ₁ in arc form connected to leadtransmission lines 205 ₁ and 206 ₁ is fixed to and provided in a hinge203 in the coupling portion between a PC main body 201 and a PC display202 so as to form an electromagnetic field connector where a coupler inarc form 204 ₂ connected to lead transmission lines 205 ₂ and 206 ₂ isincorporated inside the coupler in arc form 204 ₁ as a rotatablecylinder bush.

As shown in FIG. 51B, the couplers in arc form 204 ₁ and 204 ₂ have athickness in the direction in which the hinge 203 extends. The couplerin arc form 204 ₂ is incorporated inside the coupler in arc form 204 ₁in a cylinder bush form that is rotatable in a concentric manner. FIG.51B shows the structure in a state where the PC display 202 is open.

Alternatively, as shown in FIG. 51C, the hinge 203 may be long in thedirection in which it extends so that a signal flows in the longitudinaldirection, that is to say, in the direction in which the hinge 203extends.

Thus, an electromagnetic field coupling connector is provided in a hingeportion in Example 29 of the present invention, and therefore, it is notnecessary to connect the PC main body 201 and the PC display 202 withwires.

EXPLANATION OF SYMBOLS

-   10 ₁ First module-   10 ₂ Second module-   11 ₁ First insulating substrate-   11 ₂ Second insulating substrate-   12 ₁ First coupler-   12 ₂ Second coupler-   13 ₁, 13 ₂, 14 ₁, 14 ₂ Input/output connection lines-   15 ₁, 15 ₂, Transmitter/receiver circuits-   16 ₁, 16 ₂ Electromagnetic shield layers-   17 ₁, 17 ₂ Missing portions-   18 ₁, 18 ₂, 19 ₁, 19 ₂ Surface layers-   40 Main substrate-   41, 41 ₁, 41 ₂, 51, 51 ₁, 51 ₂ Coupler components-   42, 42 ₁, 42 ₂, 52, 52 ₁, 52 ₂ FPCs-   43, 43 ₁, 43 ₂, 43 ₃, 53, 53 ₁, 53 ₂ Couplers-   44, 44 ₁, 44 ₂, 45, 45 ₁, 45 ₂, 55, 54 ₁, 54 ₂, 55 ₁, 55 ₂ Lead    transmission lines-   46, 56 Transmitter/receiver circuits-   47, 47 ₁, 47 ₂, 57, 57 ₁, 57 ₂ Planes-   48, 48 ₁, 48 ₂, 58, 58 ₁, 58 ₂ Missing portions-   49 ₁, 49 ₂, 59 ₁, 59 ₂ Surface layers-   50 Child substrate-   61, 61 ₁, 61 ₂ Terrace members-   62 Support member-   63 ₁, 63 ₂, 64 ₁, 64 ₂ Bonding wires-   65, 66 Semiconductor integrated circuit apparatuses-   67, 68 Transmitter/receiver circuits-   69 ₁, 69 ₂ Dielectric bodies-   70 First module-   71, 81, 91 FPCs-   72, 82, 92, 92 ₁, 92 ₂, 93, 93 ₁, 93 ₂ Couplers-   73, 74, 83, 84, 94, 95 Lead transmission lines-   75, 85 Semiconductor integrated circuit apparatuses-   76, 86, 96 Planes-   77, 87 Semiconductor chips-   78, 88 Bumps-   79, 89 Bonding wires-   80 Second module-   90 Third module-   92 ₃, 93 ₃ Terminal resistors-   97, 98 Surface layers-   99 FR4 substrate-   100 PCB-   101 FR4 substrate-   102 Plane-   103, 104 Surface layers-   110 ₁, 110 ₂ Modules-   111 ₁, 111 ₂ FPCs-   112 ₁, 112 ₂ Couplers-   113 ₁, 113 ₂ Lead transmission lines-   114 ₁, 114 ₂ Termination lines-   115 ₁, 115 ₂ Planes-   116 ₁, 116 ₂ Missing portions-   120, 150, 160 First modules-   121, 131, 141, 151 ₁, 151 ₂, 161 Couplers-   122, 123, 132, 133, 142, 143 Lead transmission lines-   124, 134, 144, 154, 164 Semiconductor integrated circuit apparatuses-   125, 156, 165 RF4 substrates-   126, 158, 159, 167, 168 Surface layers-   130 Second module-   140 Third module-   152, 153, 162, 163 Lead signal lines-   155 Connection transmission line-   170 ₁, 170 ₂ Packages-   171 ₁, 171 ₂ Substrates-   172 ₁, 172 ₂ Couplers-   173 ₁, 173 ₂ Caps-   174 ₁, 174 ₂ Bumps-   180 ₁, 180 ₂, 180 ₃ Coupler components-   181 ₁, 181 ₂, 181 ₃ FPCs-   182 ₁, 182 ₂, 182 ₃ Couplers-   183 ₁, 183 ₂, 183 ₃, 184 ₁, 184 ₂, 184 ₃ Lead transmission lines-   185 ₁, 185 ₂, 185 ₃ Planes-   186 ₁, 186 ₂, 186 ₃ Missing portions-   187 ₁, 187 ₂, 187 ₃, 188 ₁, 188 ₂, 188 ₃ Surface layers-   190 Insulating substrate-   191 ₁, 191 ₂ Couplers-   192 ₁, 192 ₂, 193 ₁, 193 ₂ Lead transmission lines-   194 ₁, 194 ₂ Planes-   195 ₁, 195 ₂ Missing portions-   201 PC main body-   202 PC display-   203 Hinge-   204 ₁, 204 ₂ Couplers in arc form-   205 ₁, 205 ₂, 206 ₁, 206 ₂ Lead transmission lines-   210 ₁, 210 ₂ Modules-   211 ₁, 211 ₂ Substrates-   212 ₁, 212 ₂ Signal lines-   214 ₁, 214 ₂ Resistors-   215 ₁, 215 ₂ Semiconductor integrated circuit apparatuses-   224 ₁, 224 ₂ Feedback lines-   225 ₁, 225 ₂, 226 ₁, 226 ₂ Transmission lines

The invention claimed is:
 1. A directional coupling communicationapparatus, comprising: a first coupler in arc form provided on a firstinsulating substrate, where an input/output connection line is connectedto a first end, and either a ground line or an input/output connectionline to which an inverse signal of a signal to be inputted to theinput/output connection line connected to said first end is inputted isconnected; and a second coupler in arc form, where an input/outputconnection line is connected to a first end, and either a ground line oran input/output connection line to which an inverse signal of a signalto be inputted to the input/output connection line connected to saidfirst end is inputted is connected, wherein the diameter of a coupler insaid second coupler in smaller than the diameter of a coupler in saidfirst coupler, and said second coupler is incorporated inside said firstcoupler so as to be freely rotatable around said first coupler in aconcentric manner.
 2. The directional coupling communication apparatusaccording to claim 1, wherein said first coupler and said second couplerare provided to a hinge portion of a housing that can be freely openedand closed.